HTGuide Forum - Dayton RS WMTW Center & TMWW Mains

dawaro

08-23-2005, 10:50 PM

Notice pricing has increased for all the designs in this section of the forum. People should use the BOM's and check with suppliers for current prices

For a summary of the key information posted in this thread click HERE (http://www.htguide.com/forum/showthread.php4?t=22393)
==================================================
UPDATED 6/14/06
:E There has been a lot of discussion about both a WMTW center channel and TMWW mains using the Dayton RS drivers so I decided to start a thread on a design for both. In talking with Jon and cjd it was decided the best route would be dual RS225's with the RS28 and RS150. The center is a sealed cabinet with a .707 Qtc. The main towers have both sealed and ported versions although I think the consensus is the sealed sound the best.

There are three versions of the xover for the center supplied by Dennis Murphy, Curt Campbell, and Jon Marsh. I figure between the three designs there should be something to fit all tastes and budgets.

Currently only Dennis and Curt have completed designs for the WWMT.

Dennis Murphy has done the measurements for both the WMTW and the TMWW. I have the files if anyone is interested in them, just send me a PM or e-mail.
Myself I can not take credit for anything other than buying the drivers and building the enclosures.

Attached are files for the versions by both Dennis and Curt. Each zip file has the xover network and a standard BOM for the xovers.

We're posting updates and references below since the thread has gotten so long

Post 257 has the Dennis' tower design using the Seas tweeter
Post 568 has Curt's RS28 tower design.
Posts 569 & 579 have a very nice set of CAD drawings for all the cabinets.
See the attachments for the lastest versions of the xovers

Ported Tower CAD Drawing (http://i169.photobucket.com/albums/u225/dawaro/Dayton%20HT/RSWWMTPortedTower.png)
Sealed Tower CAD Drawing (http://i169.photobucket.com/albums/u225/dawaro/Dayton%20HT/RSWWMTSealedTower.png)
Center CAD Drawing (http://i169.photobucket.com/albums/u225/dawaro/Dayton%20HT/RSWMTWCenter.png)

Added by moderator....

People should read this website regarding the placement of inductors prior to building their crossovers.
http://www.troelsgravesen.dk/coils.htm

Dennis's crossovers call for the following drivers:

DAYTON RS28A-4 Unshielded http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=275-130
DAYTON RS150S-8 Shielded http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-362
DAYTON RS225S-8 Shielded http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-366

tktran

08-24-2005, 08:01 AM

This sounds very interesting!

What are the dimensions of the TMWW and what kind of sensitivity (dB/W) are you expecting?

Thanks for sharing.

cjd

08-24-2005, 12:04 PM

Dennis's will be harsh I think. :) I roll the RS150 off faster than that in my MTM's with a similar crossover point and I *still* find it contributes some harshness to the sound.

Any chance I can get those measurement files? I'm very curious to plug them into the design work you and I already went through, you know? :) I can refrain from publishing them if anyone would feel toes were stepped on by doing that. But I'm always curious to test my design process.

C

Brian Bunge

08-24-2005, 12:36 PM

Those look pretty good! I'm a little confused with the top view of the enclosure. What exactly are those pieces running front to back behind the drivers? Are they just strips on the top and bottom to help brace those panels better?

I've never heard any of Dennis' designs but Curt has done a few designs for me before using the standard Dayton aluminum cone 5.25" and 7" drivers and I felt they came out very well. One thing is for sure, he really seems to end up with a flat frequency response.

cjd

08-24-2005, 02:12 PM

I don't have any doubts about Dennis's ability to do excellent work - his designs are usually VERY well received (mudslingers aside). I'm just being picky, as I have some direct experience with the RS150's.

:)

C

Brian Bunge

08-24-2005, 02:25 PM

Chris,

Oh I figured you were just being picky. I can be a bit picky at times as well, even without the up front experience! ;)

BTW, did your drivers show up yet? If they aren't there today let me know.

dawaro

08-24-2005, 03:05 PM

Brian - Those are just H braces to with panel vibrations.

Chris - I will send you the files this afternoon. They are really geared around LspCAD because you have to set the driver placements with them so I am not sure how they will work in SW.

Since Dennis has the cabinet and the drivers he ran the LspCAD emulator on these for several days. In his words the speaker sounds like his CA0W1 but with deeper bass. He stated that he really likes these speakers. He had a $3500 Norh Marble special edition and these were very similar in sound to them.

cjd

08-24-2005, 03:32 PM

Brian: I'll know when I get home. But not till then. Usually PE is a 3-say trip to me I think.

On the files: If they're the right type, I can work with 'em. Close enough. :) If not, ahh well. :)

C

Brian Bunge

08-24-2005, 03:56 PM

Damn, Ohio to Illinois is that long? If I place an order on Monday I receive the order on Wednesday. Well, except for those RS 10" subs that Darren sent me. I received them next day!

dawaro

08-25-2005, 09:32 AM

tktran here is the initial layout for the tower.
http://home.houston.rr.com/roberts17207/Tower%20Layout.jpg

I would imagine that the sensitivity is going to be around 84-85db but that is just an estimated guess.

Chris - Did you get the files? Can you use them?

JonMarsh

08-25-2005, 11:23 AM

Well, I'm still trying to find my way out of the swamp at work, (not having much luck- the pending deadlines are going to keep my pretty busy over the next few weeks), but I have started on the WMTW center channel design, using the measurement data files from Dennis, and the Modula MT Elaine Marie with RS tweeter as the starting point (trying to keep the component count down).

However, note that I said "trying".... ;) I'll still probably be the parts count King unless I get lucky, because I'm a pretty firm believer (like Chris) of ruthlessly supressing the breakdown modes- and 20-30 dB down isn't enough, IMO. No mister "nice guy" crossovers from me... no kinder, gentler slopes... :naughty:

And I am trying to minimize the LF workload on both the RS28A and RS150- I'm not really keen on seeing the RS28A only down 20-25 dB in the 500-750 Hz area. OK, so maybe Darren has me pegged; this will be another "Tweakazoid" special... :rofl:

I'm still working on the IBM Power and Cooling Symposium paper (yeah, a day late and a dollar short), and then there's ICSCRM2005, plus an APEC Seminar digest to write (the guys in Villach and Munich are on holiday), and some peer review stuff to do for an upcoming IEEE conference. Can you spell, "snowed under"? ;)

And then, there's the siren call of the four Peerless 830884's, just waiting for me to measure and try out in the Arvo's.... :B

~Jon

dawaro

08-25-2005, 11:44 AM

Jon - That is what I was actually looking for out of your xover. The no holds barred approach. I figure that will give us three different versions that should fit just about everyone.

Myself I am waiting to see your Alice Cooper xover before I build anything...

cjd

08-25-2005, 12:15 PM

dawaro

08-25-2005, 01:16 PM

I still have to build the test cabinet for the TMWW and send it to Dennis to do the measurements. I am hoping to get that completed this weekend but right now the warden has me on the paint crew painting the exterior of the house. With the tropical storm in the gulf it looks like we might get a little rain this weekend so I can break off the painting and get the cabinet done.

JonMarsh

08-25-2005, 01:49 PM

Sensitivity SHOULD be much higher IIRC. I put together a design for towers with this combo a good while ago.

I got the files, but spent the evening working on baffles for the big bad RS3-ways. :) I think they'll work for me though.

I'll be plugging this data into the CC model I did, but also will toss it at the towers I put together just to see what I see. If you have measurements for the tower version, those would be nice to have too. :)

I must admit, I agree with Jon on the tweeter - was the second thing I noticed, and my second point of "hmm, not sure how well that might work or not". (the other I've already mentioned).

At modest/moderate playback levels, say, 70's to mid 80's, might be OK, but I'm an old live music kind of guy, incl. classical, and that means peaks to the high 90's or low 100's. One of the things I really like about the Modula MTM's (hats off to the Dayton drivers, too) is how cleanly and with how little compression they handle dynamic peaks. I'd certainly like to preserve and if anything, improve on that characteristic for "bigger" Dayton style systems.

The nice thing about all the magazine articles and papers I'm doing this year, is that I get a little extra money for that (publication bonuses), and that should help fund the dozen or so RS 10" HiFi sub drivers I'm going to need for the Saint Saens.... :B :T

~Jon

cjd

08-25-2005, 03:07 PM

I'm an old live music kind of guy, incl. classical, and that means peaks to the high 90's or low 100's.

I wonder how much real-world music preference and experience has to do with our ultimate design philosophies? I find it interesting that ALL of my youth was immersed in classical music with some jazz, plus some other stuff mixed in, and I have also found that the little things I find I prefer/gravitate to as far as solutions are quite often heading right towards your current state in design philosophy. :)

Dunno, but Diana Krall bores the hell out of me. Rock music is all synthetic. Jazz club is tougher, but not really too difficult. Show me a speaker that can handle Mahler's 8th in full, and I'll be impressed. Haven't met one yet (the RS150 based MTM really does try, but just gets overwhelmed. Fingers crossed on the big 3-ways! My wife isn't even complaining about the size... yet :B might when the boxes get assembled)

I've measured 30dB+ dynamic range on Pines of Rome, and it's not what it should be. I'm guessing live it woudl be 50dB or more. May be a limitation of the recording, or some of my playback equipment. Oh yea... I measured the same range from 40-70dB and from 60-90dB. :) RS's are REALLY something.

C <-- opinionated bastard :)

Brian Bunge

08-25-2005, 04:13 PM

While my interests lean more towards rock music, I can appreciate wanting a speaker that can handle the dynamics of classical music, and particularly any type of percussion instrument.

Yeah, Diana Krall bores the hell out of me as well. She can be nice to look at, and does wonders for curing insomnia but other than that, I just don't get it.

JonMarsh

08-25-2005, 08:11 PM

Yeah, Diana Krall bores the hell out of me as well. She can be nice to look at, and does wonders for curing insomnia but other than that, I just don't get it.

:rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl: :rofl:

Well, I'd say something silly, like, "Diana must be an aging yuppie boomer kind of thing", but then I'd probably come under that description, and my sentiments are in alignment with yours.... :T

For those who do like Diana, please, don't take any offense- just different strokes for different folks.

~Jon

dawaro

08-25-2005, 08:59 PM

I should note again that the design from Dennis was developed using the emulator in LspCAD so it more than just a simulation. When it is possible he prefers to use 2nd order slopes. He worked up both a 2nd and 4th order version of the xover. After listening to both on the emulator he prefered the blend of the 2nd order over the steeper slopes. In his own words "I can't say as I've heard any harshness".

tktran

08-25-2005, 09:14 PM

cjd,

I wonder if the cabinets could be reduced in width?

The inner cutout of the RS225 is 7 3/8" according to the PE website, and I like to build speakers as slim as possible, as long as it doesn't compromise on the design (but usually does)

A request if you haven't built it yet- if side wall thickness is 1", have you considered building it 9.5" wide?

regards,
Thanh.

PS. I first heard Diana Krall 3 years ago, from a friends CD-R. She was singing standards and I thought she sounded incredible (Nina Simone?). A couple of years later I bought this CD and was shocked!

I recently saw her live and had no idea she's 40...

dawaro

08-25-2005, 10:20 PM

The outer measurement of the RS225 is 8.75" and the cabinet is built with a .75" round over so there is only .25" of unused space on the width.

Dennis Murphy

08-25-2005, 11:08 PM

Just to clarify a little, my design is second order acoustic between both sets of drivers. Curt's crossover is 2nd order between the woofer and mid, and 4th order between the mid and tweeter. I have built my crossover and listened for maybe 2 or 3 hours. I like it, but that's not to say I wouldn't like Curt's better if I built it. I will compare the two approaches on the lspCAD emulator tomorrow. I generally prefer 2nd order designs, but obviously there are no iron-clad rules, particularly when you're working with a driver (the mid) that has definite break-up issues.

Brian Bunge

08-25-2005, 11:38 PM

Dennis,

That would be great! I'd love to hear what you think of one design vs. the other.

tktran

08-26-2005, 06:15 AM

The outer measurement of the RS225 is 8.75" and the cabinet is built with a .75" round over so there is only .25" of unused space on the width.

I wish I knew how to veneer cabinets with roundovers...

dawaro

08-26-2005, 09:22 AM

tktran, there are several differnet ways that you can do it. Most veneer will easily make a .75" bend so you can simply wrap the veneer around in one piece. Just start on one side and wrap it around the front to the other side. Like this one:
http://www.zalytron.com/pictures/budg102.jpg

My cabinets are like the PE cabinets with a removable front baffle. The baffles are painted flat black and the cabinets are oak veneer with a black analine dye to match the TV and equipment rack. I just veneer the cabinet like you would normally.
http://www.partsexpress.com/imageslarge/302-750i.jpg

Andy_G

08-26-2005, 09:54 AM

[QUOTE=tktran]
A couple of years later I bought this CD and was shocked!
[QUOTE]

Yep, that album was, I think, an attempt by the record company to make Diana like Norah Jones. They succeeded..... boring... and lifeless !!!
I sold the CD to a 2nd hand store the day after I bought it !!!

Never could understand why people found Norah Jones interesting ? :confused:

Try the Live in Paris album, that's Diana !!

JonMarsh

08-26-2005, 11:01 AM

Funny you mention that, that's the one Diana Krall album I do have- hybrid SACD.

It certainly is more to my tastes than her other offerings from the record company.

~Jon

Dotay

08-26-2005, 11:54 AM

The baffles are painted flat black and the cabinets are oak veneer with a black analine dye to match the TV and equipment rack.

Do you have any pictures of your speakers with the black dye? I am thinking of doing something similar with my subwoofer I am building.

dawaro

08-26-2005, 11:58 AM

I can take some pictures of the Modula MT & MTM's that were done that way and post them when I get home tonight.

Here is a speaker that was done with the aniline dye.
Audax Center (http://www.sdinfo.com/volume_8_3/diy-13-audax-center-channel-speaker-9-2001.html)

Dotay

08-26-2005, 12:11 PM

OK, I guess what I want is more of a stain then. I am wanting something that will be more translucent to show the wood grain but not a solid black like that. Any suggestions?

cjd

08-26-2005, 12:51 PM

How's this?

http://www.eldamar.net/audio/rs150mtm/graphics/P0000519.jpg

Minwax Ebony stain on Birch.

Can be laid down lighter, but it takes on an ever more brown (still very rich and dark) hue.

C

Brian Bunge

08-26-2005, 01:19 PM

If you have trouble finding the minwax stuf, Olympic has a "deep ebony" stain which looks pretty much the same. It actually looks quite nice on oak veneer. Unfortunately, I don't have any pics to show off.

cjd

08-26-2005, 01:24 PM

Oak or ash should take the Ebony stain *very* well I would think. Oak is particularly affordable to work with. :)

C

tktran

08-26-2005, 01:26 PM

Yep, that album was, I think, an attempt by the record company to make Diana like Norah Jones.

Actually, Diana came first. I think her first album was about a decade before Norah's.

Now I remember the first one I heard - When I look Into your Eyes, only a few years ago, and that was really good...

Joe L.

08-26-2005, 01:37 PM

These examples of the "analine dye" finish are the enclosures I built for my home-theater. They are part of the Audax HT series.

They are finished with black analine dye over oak veneer. You can easily see the grain of the wood. You can then cover the dye with anythng from dead-flat lacquer to glossy.

Here with dead-flat-clear lacquer as a finish
http://home.triad.rr.com/leggio/images/ht/projects/P4270742a.jpg

I personally prefer the dead-flat finish as the "satin" finish on my center channel has way too much "gloss" to be used near my front-projection screen as it reflects a lot of light and is distracting.
Here is my center channel with the same analine dye and a "satin" poly finish.
http://home.triad.rr.com/leggio/images/ht/projects/Pa290362.jpg

Joe L.

Dennis Murphy

08-27-2005, 05:13 PM

Dennis,

That would be great! I'd love to hear what you think of one design vs. the other.

Well, I lugged the big hog center channel up to the emulator room today and compared my design with Curt's. I also listened to mine with just the 150 playing (with my crossover in line) to see if I could pick up on any harshness from the upper end response. But that was all secondary to the major issue, which is that Curt's approach--cutting the tweeter off very sharply, but running it out all the way to around 1600 Hz--overtaxes even this great unit, and the result can be pretty painful. Switching back to my design eliminates the treble harshness, so I have to conclude that suppressing the lower end of the tweeter (near resonance) by more than I've done is not nearly as important as keeping the tweet within its comfortable operating range higher up in its passband.

For what it's worth, I couldn't hear any hint of the 150's breakup when I just listened to the midrange using my 2nd order ntetwork, even on very heavily orchestrated music with lots of brass and upper treble. Finally, I listened to mine last night for about 3 hours, comparing it with other speakers I had around. It gives the kind of sound I like--clear and open midrange, with an extended high end--with the excellent blend you get from 2nd order acoustic crossovers using drivers that are up to it. So I'm signing off on this one, and looking forward to designing a complementary Left-Right second-order 3-way.

Of course, I had a tremendous advantage in being able to actually build, listen and tweak my design. I think Curt might want to consider modifying his otherwise excellent 4th by moving up the tweet crossover to around 2100 Hz. And I really hope Jon comes up with a super-no-holds-barred eliptical slope approach. I've never heard one of his designs, and am looking forward to it. Oh--and thanks to PE for the great drivers.

JonMarsh

08-27-2005, 05:56 PM

Hi Guys,

I'm out the door for some errands, but later this weekend I should have a proposal up- it's looking pretty fair so far, but I'm afraid I really took David's inputs about a "no holds barred" approach a bit too seriously... ;) It owes a lot to the Arvo Part crossover, so it's not "cheap", I'm afraid.

I've also worked on an approach more like the Natalie P, but I'm not too happy with that yet.

I've got a little more tweaking to do, but it's falling into place fairly well, well enought that I'll probably just have to build one of these for my own "Uber center channel". ;)

I won't be able to setup and listen to an emulation right away, so if you have the time to play with this when I get it posted, Dennis, that would be very interesting.

~Jon

Dennis Murphy

08-27-2005, 06:17 PM

Hi Glad to hear you'll be joining in. I would be happy to give it a whirl on the emulator. I'll be in Michigan all day tomorrow taking a listen to the future. Jim Salk has worked up a version of his HT3 speaker (that I did the passive for) using the magic DEQX box. It will be worth the trip (assuming Northwest is still getting those birds up in and down from the air) to see whether I can really hear the the advantages of the optimized phase, room eq, and steep slopes, or whether there will be digital artifacts.

JonMarsh

08-27-2005, 10:07 PM

I'll be very curious to hear your thoughts and impressions on the DEQX, Dennis. One of our acquaintances in Denver, "Denver Doc" has gotten one and is really in love with it, but I've never had a chance to hear it or try it out. I think it would be very interesting to compare it with a high quality conventional passive implementation in which it emulates the transfer function of the passive version (like the LspCAD emulator) as well as listen to some of the more advanced modes. My understanding, though, is that the digital filters don't truly remove all phase shift, there are artifacts such as those inherent to most CD playback systems, such as the pre-ringing on 1 kHz sq. waves. Are they audible and/or deletrious? Don't know-

I'm something of an audio luddite, so I tend to be skeptical. I also think that in evaluating this kind of approach you do have to have reference associated equipment and sources. Otherwise you're run the risk of just doing "lateral" comparisons- things sound different, but not necessarily more faithful to the original music.

Some reviewers I respect do feel the DEQX introduces some veiling and reduction of soundstage depth. OTOH, it may fix a lot of things for some systems, and be fairly worthwhile in the right applications. I've considered getting something like that for "prototyping", but when I stop and think about it I figure I'm probalby better off just getting a better Maudio multi-channel sound card and sticking with LspCAD Pro.

BTW, I'm not much in favor of using equalization to fix room problems, because at best the'll only be fixed for the primary incident sound in one location, and the reverberent sound field could get pretty screwy. Just my 0.02. Still, I'm curious about your educated opinion.

~Jon

cjd

08-27-2005, 11:08 PM

Hmm... you're not using the shielded tweeter, eh?

Plugged it into what I had worked up a while back with simulated data - not quit there. Not horrible, but not great. I see different impedance than I worked with though, kinda interesting really. No luck tweaking this evening, but I think I'm half brain-dead. :)

I wonder how Curt's would work with a steeper filter on the tweeter. ;)

C

Dennis Murphy

08-28-2005, 12:00 AM

Hi The slope is plenty steep. The problem is in the pass band. This just isn't a tweeter you want to push that hard.

Dennis H

08-28-2005, 12:57 AM

Dennis, I wonder if the QC issues with the RS tweeter are biting you? Mark K measured some to be very clean, among the best below 2K, and others not so good with various nasties down low. Jon has had good results (with good samples?) crossing at 1400 with his CE filter that emulates an LR8 for the initial rolloff. Do you have some other RS tweeters you can try?

JonMarsh

08-28-2005, 11:25 AM

Hi The slope is plenty steep. The problem is in the pass band. This just isn't a tweeter you want to push that hard.

Dennis, we've seen some variability in RS28a's, as regards LF distortion; most are pretty killer, hanging right in there with the Millenium Excel (which generally works fine in an LR-4 at 1500Hz), while a few, according to MarkK, have had higher distortion below 2 kHz. I'm wondering if there isn't a QA issue in their assembly process, but maybe you've got one that's a little less optimum. Dunno what to suggest apart from that, if you think it's in the working passband.

You've got Praxis, I believe? Maybe you want to take a look at that puppy. Later this fall I'm going to get setup for distortion measurement and test all of the ones I have.

~Jon

Curt C

08-29-2005, 12:52 AM

Gentlemen,

Sorry I’ve not jumped into this thread previously, but like Jon, work keeps intruding.

I’m a little puzzled by the tweeter performance when Dennis emulated my design. I’m currently listening to another 3 way design using the RS28. The tweeter fc is slightly higher in this design at 1650 Hz, but with only a 3rd order slope. These will play at very high levels without any audible distortion. In this design, the tweeter transfer function is actually somewhere between 5th and 6th order at 1500 Hz, so one would surmise it would an acceptable fc.

Looking at the .zma plots of the tweeters in both designs doesn’t reveal any obvious differences or aberrations pointing to a defective tweeter, but I suppose it still could be a mechanical defect. Any comparisons of the .frd plots between the two designs is a little more nebulous due to the differing diffraction effects.

I did not have the capability to emulate the design as Dennis has, so at this juncture, I would suggest anyone running out and building this center channel should not use my design until the mystery is resolved. It will be interesting to see what design Jon cooks up and if he also has to cross higher.

C

Dennis Murphy

08-29-2005, 01:05 AM

Dennis Murphy

08-29-2005, 01:07 AM

Hi I just got back from Motor City, where I spent the day listening to the HT3 with my passive and a DEQX version that we worked up on the spot. I'll give a detailed report tomorrow, although it would have taken at least another day of listening for me to reach any really firm conclusions. Audio is complicated.

dawaro

08-29-2005, 10:43 AM

For those that are waiting for the TMWW I got the the test enclosure built last night. Tonight I have to put the round over on the baffle and then cut a perfectly good cabinet in half (to make it easier for Dennis to lug it up and down the stairs). Hopefully all will go well with that tonight and I can get it shipped to Dennis either Tuesday or Wednesday. At 42"h x 10.75"w x 18.375"d this one should put me in the UPS prefered customer program...

cjd

08-29-2005, 11:45 AM

I wonder if it would be cheaper for Dennis to find a local cabinet maker to manufacture?

Just a thought. ;)

I know how heavy (and HUGE) the big 3-ways are that I've got going (thanks to Brian B of course)...

C

dawaro

08-29-2005, 12:11 PM

Actually shipping isn't going to be that bad. Probably about $40.00.

JonMarsh

08-29-2005, 12:20 PM

OK, I haven't posted yet, but that's because I'm still refining and removing components... yeah, taking out parts, that's a good thing, right?

One of the things about this effort that does give me pause is the relationship between the raw driver response, the response on a specific baffle (which due to baffle effects changes on axis, and off axis, but not the same for both), and what target to use for the final response via the crossover.

Usually I spend a lot of time on the enclosure design, baffle layout, and drive positioning so that the baffle issues have relatively minimal or at least controllable effects on the driver passband FR. With a design like this kind of center channel, the layout tends to be dictated more by the space considerations than the acoustical properties. I'm suspecting this is what results in some of the "wavies" I see in the FR plots that I'm not usually having to deal with in some other cabinet designs. Sometimes I'm a little concerned about equalizing out those things "on axis", because the driver launch in other directions may not have the same characteristics or issues, and we need to consider the off axis response as well as on axis.

Well, it's getting pretty close, so maybe by this evening I'll be willing to post it for you guys to critique. I need to look at the LF stuff in a little more detail. Also, I don't completely trust what LspCAD predicts as the interaction between the LF crossover and the driver impedance.

Still, this is looking pretty promising, and I imagine this could be a pretty nice CT overall. Might have another cabinet building project for this Xmax.

~Jon

dawaro

08-29-2005, 01:03 PM

The layout as you mentioned was really dictated by the real estate that was available. One of the things I tried playing with was the position of the RS225's. From the sims I ran with BDS there appeared to be fewer major dips with them in closer to the center axis of the enclosure. This is pretty much the same layout that Adire uses for their LCR speaker.

cjd

08-29-2005, 02:29 PM

As I'm thinking on this, I note that the RS150 response is significantly different than the predicted models I was working with previously - the tweeter and woofer(s) response is quite close to predicted.

I did not look at the RS150 data specifically at all (in fact, just tweeter impedance to determine whether I was dealing with the shielded version or not) but am kind-of curious about that now. :)

I think my other problem was once again getting the driver offset backwards when working with the predicted models. :oops:

C

JonMarsh

08-29-2005, 03:32 PM

Chris,

Working on this has gotten me even more interested in looking at the WWMTM project you've been working on. Having good measurement data is so critical, though. I may get another set of PE cabinets and some RS150s to slap together just to see for myself how it all looks- but WHERE am I going to store all this stuff?!? Bedroom HT? Maybe one in my daughter's room, too? ;)

Jim Holtz

08-29-2005, 03:49 PM

Dennis Murphy

08-29-2005, 04:11 PM

Hi It's off-topic here, but I just posted my reactions to the DEQX system on the Parts Express and Madisound board ("I took a listen to the future yesterday...").

JonMarsh

08-29-2005, 05:58 PM

Thanks for the heads up, Dennis.

~Jon

JonMarsh

08-29-2005, 06:10 PM

Hi Jon,

Isn't the 3-way that Dewaro and Dennis are working on for mains the same as the 3-way discussed in the H1212 thread except for the tweeter? Just curious if you've had a chance to revisit the H1212 design you mentioned that you were doing for a friend?

Jim

That's right, Jim! I've got some H1212's on order, too.

This is probably going to be a little like the Modulas, where we wind up with several permuations- while Dawaro wants an WWMT tower, I'm likely to proto a WWMTM instead, as the increased vertical height lessens effects from floor bounce.

Then, there's WLS who would like a three way with the H1212, RS150, and RS270. What's not to like? Sort of a mini-Sophia. Well, actually, not mini, when you think about it. (except that the midwoofer is slightly smaller). And that would be about 1/2 of my Max Klones, which will have two 270s, and the X1 SLAMM uppers, but upgraded on the midwoofer side.

While I can imagine building all of these, I'm having trouble imagining what I'd do with them. In past days I gave speakers away to my girlfriends, but work has been so non-stop I just hardly have a personal life these days.

~Jon

Brian Bunge

08-29-2005, 06:43 PM

Jon,

Keeping enough girlfriends around to give all these speakers to could get rather expensive as well! :)

Jim Holtz

08-29-2005, 08:16 PM

Jon,

Sorry if it sounded as if I was pressing. I wasn't. :) I was just curious due to the similarity in designs.

Best regards,

Jim

That's right, Jim! I've got some H1212's on order, too.

This is probably going to be a little like the Modulas, where we wind up with several permuations- while Dawaro wants an WWMT tower, I'm likely to proto a WWMTM instead, as the increased vertical height lessens effects from floor bounce.

Then, there's WLS who would like a three way with the H1212, RS150, and RS270. What's not to like? Sort of a mini-Sophia. Well, actually, not mini, when you think about it. (except that the midwoofer is slightly smaller). And that would be about 1/2 of my Max Klones, which will have two 270s, and the X1 SLAMM uppers, but upgraded on the midwoofer side.

While I can imagine building all of these, I'm having trouble imagining what I'd do with them. In past days I gave speakers away to my girlfriends, but work has been so non-stop I just hardly have a personal life these days.

~Jon

Mark K

08-29-2005, 09:36 PM

cjd

08-30-2005, 01:39 PM

Having good measurement data is so critical, though.

Which is why I have two cabinets nearing completion, and a suite of drivers ready to go. :) I have to flush-trim one cabinet, add the baffle chamfer when the bit shows up, sand and finish.

Measurement equipment is standing by.

My only worry is I won't be able to get these set up out-doors for measurements - may have to make do indoors. Just too heavy for me to do myself. If that bit shows up in time, expect to see real measurements posted on Friday! :)

Even if it doesn't, I may slap some drivers in and take some measurements just to see, knowing that it will change somewhat (mostly tweeter ripple should be greatly reduced if the modeling is to be believed). :)

In fact, I believe it was some discussions I had on this center channel project that initiated Dennis's involvement - at any rate, I remember being uncomfortable with the small differences we couldn't explain in who was running the sims, combining response, tools used to model, etc. :)

C

Brian Bunge

08-30-2005, 01:56 PM

Chris,

Ummm...ever heard of a hand truck? ;) I know, I know, what purpose does the average person have for keeping a hand truck around, right?

cjd

08-30-2005, 03:17 PM

Chris,

Ummm...ever heard of a hand truck? ;) I know, I know, what purpose does the average person have for keeping a hand truck around, right?

How does that get it up in the air four feet?

Also, solo with hand truck + heavy load + cats can be a bit tricky too. ;)

C

Dennis Murphy

08-31-2005, 11:39 AM

Hi I was pretty surprised as well, because the Orion takes the Millennium down to 1600 Hz with no problem. Since the problem was obvious with just the tweeter circuit engaged on the emulator, I may build your high pass circuit for the tweeter and listen to it and my 2nd order. The emulator is pretty reliable, but you never know........ In any event , I only have one tweeter.

I got a chance to build the high pass filter and listen last night. Obviously a fair test would require me to build the entire 4th order crossover, but I just have too many other projects pending to do that. I heard the same signs of distress, and, to check whether it was just a QC problem, I hooked up the Usher textile tweeter on which the RS is based. The sound was basically the same. I personally don't think even low Fs tweets should use a 15 uf series cap--that just seems to be asking for trouble. But I know some of you have done that and like the results, so I won't comment further. Different strokes..... Anyhow, I'm really enthusiastic about the prospect of doing the main 3-ways, and seeing other approaches. I think a lot of choices and good sound will come out of this project.

cjd

08-31-2005, 11:52 AM

Hey Dennis,

Can you share some of what you're listening with (not the actual stuff, just titles and such so we can acquire it if we don't have it) and where you're noticing some of this distortion in particular?

I'm getting ready to test the RS tweeters I have and was planning on a lower crossover point (~1400Hz to RS180's) and figure, well, while I'm at it some testing might be advisable. :) If I weren't knee deep in another project I would put more time into revising the prototype work I did on this stuff. May dig in and do so anyhow somewhere along the line.

What do you need equipment-wise to get full emulation out of LSPCad? Multi-channel sound card and an amp per?

C

Dennis Murphy

08-31-2005, 02:00 PM

Hi I listened to everything from cool jazz to Wagner at full cry. It didn't really matter--the strain was apparent on just about any program material. For the emulator, I use the Delta 410 card and an Outlaw 6-channel HT receiver.

cjd

08-31-2005, 02:05 PM

Hmmm. Delta 410 is already on my list. Multi channel amp is too, just not so soon.

LSPCad though, not there. Yet.

I wonder how Dan Cyr is coming on his crossover software. I watched him tweaking with it last year at DIY Chicago, but we never heard the results. I offered to lend a hand trying to give it a UI that's useful, but it's been all quiet. I bet he's makin' noise somewhere. Hmmmmm...

Wagner I have. I usually toss Mahler at it, as well as Orff. Sounds good. Hopefully I hear nothing bad, but my ear *would* if it were there. Never sure on my ears, y'know? :P

C

Mark K

08-31-2005, 02:08 PM

I don't know what to say. I've been using the lspCAD emulator with a parasound multichannel amp and driving the RS28 crossed at 1.2-1.3k with a Cauer filter and I don't hear any tweeter strain.

Of course I cherry picked a pair of RS28's that I know test well down low.

As far as comparisons with the Usher-well, that's not particularly helpful since the Usher doesn't go that low-or at least not the ones I've tested.

Again, my advice from before still stands. If you want to use the RS28 lower than 1.8k or so, give or take, you should test it yourself.

Dennis Murphy

08-31-2005, 03:27 PM

JonMarsh

08-31-2005, 03:56 PM

Jon,

Keeping enough girlfriends around to give all these speakers to could get rather expensive as well! :)

Yeah, well, I kind of figured that out... now I'm at the other extreme. Last set of speakers given away to a girl friend was in about 2002. Then, there was the set I built for my daughter in 2003. And there's another set in process for an artist friend from wayback who lives in upstate New York, that I get together with every now and then (usually in Montreal, or visiting her place in NY)

Maybe that's why speakers are starting to stack up around here.... ;)

cjd

08-31-2005, 03:59 PM

But if you have another suggestion, I may very well have it lying around.

One of the Seas "budget" beauties, such as the 27TDFC or TBFC (or TDC/TBC) perhaps? Obviously it will NOT be a drop-in for that specific network topology, but they have been used quite low with success as well.

C

Dennis H

08-31-2005, 04:49 PM

Mark K

08-31-2005, 05:20 PM

I don't know. The trouble with your tests, good as they are, is that they've never been validated with listening tests. I don't think we know whether the differences you're measuring would amount to that much in actual listening. What I was hearing wasn't subtle, and I'm pretty willing to bet will show up on any tweeter I throw at this particular circuit. The regular Usher is quite robust. But if you have another suggestion, I may very well have it lying around.

What was it that you were hearing? While I don't have definitive psychoacoustic tests of my tests per say, there is plenty of well documented literature that shows the negative audibility of higher order distortion that achieves levels at -60 and above.

This is well documented.

Frankly, use any reasonable test of IM distortion-it doesn't have to be mine or SL's. If the higher order distortion products are -60 dB or under, it will be audible.

I would be willing to bet money that what you're hearing is those higher order products. Hence the reason I want to test your tweeter.

This brings me to another interesting exercise.

For the diy2005 in norcal, I'll use the lspCAD emulated cauer filter in my RS28A/RS225 2 way and use different RS28's with variable distortion patterns. We'll see how audible everyone thinks these differences are. I can use a cherry picked, low distortion one, kind of an "average one," and the poorly performing one I got from Zaph.(jkrutke).

JonMarsh

08-31-2005, 07:08 PM

This brings me to another interesting exercise.

For the diy2005 in norcal, I'll use the lspCAD emulated cauer filter in my RS28A/RS225 2 way and use different RS28's with variable distortion patterns. We'll see how audible everyone thinks these differences are. I can use a cherry picked, low distortion one, kind of an "average one," and the poorly performing one I got from Zaph.(jkrutke).

That will be very interesting- I hope I'll be able to make that one.

~Jon

jdybnis

08-31-2005, 10:53 PM

Dennis Murphy

08-31-2005, 11:28 PM

I hear all of you. But I don't know--I'm still very dubious about using a 15 uf cap on any tweeter I've had experience with. The RS tweeter I have isn't mine, so I can't really send it off for further testing. But I will run a distotion test on it. I have Praxis as well. In any event, the key to any science is replication. None of this will be settled until others try both filters. I'm just telling you what I heard in one experiment.

Mark K

09-01-2005, 01:06 AM

Well, I agree about being careful. A lower xover point can be more audibly problematic for the following reason that I think gets missed.

Sure, going from say 2k to 1.5k isn't that much. Nonlinear distortion may only increase by 3-6dB. But that's only half the story. At 2k, the higher order products (rub and buzz) would be centered around 20k. Even if they are there, they aren't that audible. After all, they are at 20k.

Push the xover to 1.3-1.5k and the higher order products are now centered around 13k to 15k. Not only are they higher in spl, but they are in a more audible part of the frequency range.

Tweeters that you want to cross low have to demonstrate very low higher order products.

Dennis Murphy

09-02-2005, 11:12 AM

Hi Mark I've done all my distortion tests in the past using LAud. If it's not too much trouble or complex, could you maybe e-mail me what exact IM test you think I should do in Praxis, and maybe how to do it if it isn't obvious once I access it? Thanks! rdmurphy@verizon.net

dawaro

09-05-2005, 01:33 AM

For those that are waiting on the TMWW version here is a little update. I got tied up with some other priorities this week and did not have a chance to finish the enclosure until this afternoon.
I will get it packed up and sent to Dennis for measurements Tuesday.

http://home.houston.rr.com/roberts17207/TMWW%20001.jpg

The test enclosure is built in two pieces to make it easier to move around.

http://home.houston.rr.com/roberts17207/TMWW%20002.jpg

wls

09-05-2005, 09:15 AM

Then, there's WLS who would like a three way with the H1212, RS150, and RS270. What's not to like? Sort of a mini-Sophia. Well, actually, not mini, when you think about it. (except that the midwoofer is slightly smaller). And that would be about 1/2 of my Max Klones, which will have two 270s, and the X1 SLAMM uppers, but upgraded on the midwoofer side.

Jon, glad you still have my mini-sophia on the list :T . Except, I do want to use the RS180 as the mid since (1) I have them and (2) I want the power of the larger driver. I find drivers smaller than 6 inches too small.
- Bill

JonMarsh

09-05-2005, 12:00 PM

No problem, that's what I have around, too (the RS180), and that's also closer to the intent/design of the Wilson system. I expect to get some RS150 in for the center channel. I may also model that enclosure a little more and see if some judicious roundovers will help- I have some humongous MLCS bits.

But for today, it's back to work-work. Labor Day indeed!

~Jon

dawaro

09-05-2005, 01:15 PM

Jon is your design for the center close enough that you can publish it?

cjd

09-05-2005, 02:33 PM

Ahh, finally.

I'm gonna throw in a revision of my own effort as well, since I was already mostly there and in the tweaking mood, and finding little to tweak well on the big monster towers. . .

http://www.eldamar.net/audio/rswwmt/graphics/ccNetwork.gif
http://www.eldamar.net/audio/rswwmt/graphics/ccResponse.gif

If you leave the impedance compensation off the tweeter (the last two ladder circuits) change CT2 to 18uF and change Lt1 to .2mH, along with adding a 1ohm resistor.

You could similarly leave the zobel off the RS225's if you really wanted by upping the parallel cap to 120-130uF but that just seems quite silly to me. :)

C

JonMarsh

09-05-2005, 05:01 PM

Jon is your design for the center close enough that you can publish it?

I"m on my 4th variant of it, will get it posted before I leave on travel tomorrow. I keep wanting to try something a bit different, but I save the earlier versions in case it doesn't quite work.

dawaro

09-05-2005, 06:03 PM

Chris have you looked at the impedance on this? I loaded it in LspCAD and it looks like it stays well below 4 ohms through most of the range.

cjd

09-05-2005, 10:05 PM

Chris have you looked at the impedance on this? I loaded it in LspCAD and it looks like it stays well below 4 ohms through most of the range.

Yup. Quite nice really as it also stays abouve 3ohm. ;) (may dip very slightly below I guess, I think I see 2.973ohm)

You can drop the zobel but you actually end up with *worse* impedance as it dips below 3ohm. This should be no trouble at all for a 4ohm stable amplifier.

If your amp isn't 4ohm stable, you're going to be in trouble with *any* of these setups.

Don't look at the monsters I'm working on. ;) They have even more trouble. This tweeter is slightly tough to roll of this fast and also keep impedance up. At least, I have found it to be so. I also understand that I am still learning, and expect to learn even more. :)

Mostly, it was something I did for my own edification, and it can be completely ignored. No hard feelings. Or if Dennis is somehow finding himself bored and curious, he can try it and provide feedback. Being an artist, I'm quite used to being told that my work is garbage, why don't I just stick to being a drug-store clerk or something. ;)

C

JonMarsh

09-11-2005, 01:31 PM

OK, here it is, don't say I didn't warn you!

http://audioworx.virtualave.net/DAWCTRSchm.jpg

http://audioworx.virtualave.net/DAWCTRSPL.jpg

http://audioworx.virtualave.net/DAWCTRSPLInvert.jpg

(Inverted phase on midrange as check for crossover phase and transfer function)

http://audioworx.virtualave.net/DAWCTRZ.jpg

Z - remember, the RS28a is for all practical purposes a three ohm tweeter- lets keep that in mind when worrying about the series capacitor size values.

I consider this a "proposal" - given that there might be issues to consider with regards to levels, and I expect that some felt treatment would knock down the roughness in the 2kHz plus region. Since placement near a boundary will provide some lift below 200 Hz, I went with no midrange attentuation and adjusted everything else around that. I "think" that will proivde the best balance in the application, but of course, that could be subject to change.

This crossover started from the Arvo Pärt design; I did consider lower crossover point for the RS150, but the components got rather large rather quickly, as expected, and I think the little six will be a bit happer and more pristine in the upper mids if it isn't doing much below 300 Hz. One might also argue for putting a "Bullock bump" in the woofer to midwoofer crossover region, as the power response of an LR-4 is down in the crossover region, but with an WMW configuration, I'd rather measure before making that judgement.

For a good four ohm stable amp (do I use any other kind? Oh yeah, I mostly use 2 ohm stable amps....), this shouldn't be any problem, I hope. Phase angle at minimum Z is fairly benign.

~Jon

Steve Goff

09-11-2005, 07:25 PM

Jon,

Very Nice!

cjd

09-11-2005, 11:23 PM

Jon: Looks very good. I also find it heartening that it's similar yet different from my own proposal - similar where I was particularly concerned with mine. :) Different where I'm not sure WHY, but that's half the fun. Heh.

I can say that, in general, the RS150 should have NO troubles in the range you're using it. In fact, even doing ALL bass duty and crossing at 2100Hz 4th order I find it generally VERY pleasant and listenable. Perhaps not the best it can be, but you've given me food for thought on why I was thinking Dennis's might seem harsh yet he didn't find it so, IF the low frequency extension I have on mine and he's not dealing with plays any role. Entirely too possible. ;) More for me to investigate.

C

Curt C

09-12-2005, 12:38 AM

Originally Posted by Jonmarsh
You asked for it, you got it... complexity!

Jon,
I’m not sure what you are talking about. –It’s only 25 components! However, I can’t say I remember the last time I used an 82 AND a 68 ufd in a tweeter circuit. Chris, your design looks very good as well.

I guess we’ve come up with 4 ways to skin the same cat here. I think it’s noteworthy how similar the impedance plots are even though the individual topography of each design is quite different. Of course we won't know how different they sound until someone builds them, but I suspect their audible differences would be subtle.

C

Dennis Murphy

09-14-2005, 09:28 PM

Hi Jon A bit simplistic, but not a bad first effort. Uh--you don't happen to own stock in a crossover parts manufacturer, do you? I take it this was done in lspCAD 6.0. Am I going to be able to model it in my 5.0 version? I haven't studied it really carefully yet. If it's possible, I'll model it and listen this weekend.

Dennis H

09-14-2005, 09:36 PM

Dennis, before you model and listen, I think it would be worth your while to verify that you have a "good" tweeter. Your problems at low tweeter frequencies would seem to indicate otherwise.

JonMarsh

09-14-2005, 10:02 PM

Hi Dennis- this is one of my straight ahead CE on the tweeter and mid, just LR4 on the woofer. Yeah, it's a pity I don't get commision on each component... obviously I'd get fired on the first day working for a commercial speaker manufacturer... I'd never even make Geek of the Day, much less of the Week!

Look at a modern motherboard or sever power supply and you'll get an idea of where I pick up my bad habits. ;)

Unlike my quasi-series design (which I did at first try to incorporate in the first passes on this) (like the Natlie P design), this one can be modeled in LspCAD 5 without problems- that's where about half the initial Arvo development was done.

That's part of why I popped for LspCAD 6, besides having a schematic editor more like a true CAD simulator (I use SIMetrix for circuit simulation mostly), it will allow you to do almost any reasonable kind of circuit, plus the behavioral modeling capabilities are cool- I think it should be possible to model a dipole accurately with the right calculations, I just dont' have the time to try to sit down and figure out how to do it...

THIS would be pretty much impossible in LspCAD 5.

http://audioworx.virtualave.net/NataliePSchm.jpg

This is a low part count (for me) MTM with the RS180s and RS28a.

http://audioworx.virtualave.net/NataliePSPL.jpg

jdybnis

09-14-2005, 11:30 PM

Jon,

Have you used your CE filters for lower order crossovers? Like the LR4 on the woofer? Pete Schumacher was playing with something similar to (the same as?) CE filters about a month ago http://www.madisound.com/cgi-bin/discuss.cgi?read=352390

Dennis Murphy

09-14-2005, 11:56 PM

I have tested my tweeter. But the results were ambiguous. I would have to have a certified in-spec tweeter on hand for comparison. My instincts tell me there's nothing wrong with the tweeter, and anyhow it's all I've got. Plus--how do you know which tweeter you will end up with? Maybe the design should be robust enough to accomodate some variation in the low-end distortion specs.

Dennis Murphy

09-15-2005, 10:57 AM

One other point. If you compare the tweeter cut-offs for the last 2 designs posted with Curt's, you'll see that they start rolling the tweeter off much sooner than Curt does. I'm therefore not expecting to hear the harshness problem when I run the newest 4th order designs through the emulator this weekend. It should be interesting.

Brian Bunge

09-28-2005, 12:58 PM

Dennis,

I was just wondering if you ever got a chance to run those other other 4th order designs through the emulator.

Jonasz

09-28-2005, 02:04 PM

Dennis M: Have you found the time to listen to Jon's crossover yet?

tktran

09-30-2005, 06:08 AM

I was just doing some sketches, and came across the idea of a
floorstander. Would it be possible to tweak the crossover for the center, so that the speaker could be used when it's turned 90 degrees.

ie The centre channel could be rotated 90 degrees and be placed on stands for L/R duty, or be built into a 4 ft tall and moderately well proportioned floorstander.

L speaker:
W
MT
W

Centre:

--T--
WMW

R speaker:

W
TM
W

Something rotating like this:
http://www.dynaudioacoustics.com/Default.asp?Id=534

Brian Bunge

09-30-2005, 10:46 AM

There's always a tower design for this speaker, laid out as a TMWW, which will work much better than the center channel rotated.

The baffle layout is on the first page, and is 42"H, IIRC.

cjd

09-30-2005, 11:03 AM

Horizontal alignment of a TM usually results in poor off-axis performance, though that is not a given. Similar reasons that an MTM center is less desireable. It would have to be tested to know how well it actually works.

C

tktran

09-30-2005, 12:36 PM

Point taken.

Thanks for the intelligent feedback.

Would it be possible then to use the centre channel for L/R duty too?

Kind of like this main monitor (9"WW, 5.5" M, 1.1" T):

Brian Bunge

10-04-2005, 05:52 PM

Dawaro,

Since we're talking about the tower now, did Dennis ever finish a design for it? Also, did you ever post the cabinet dimensions for the tower? I'm not sure, but in your pictures it appears that there is a port in the back of the bottom section. Is this the case? I'm trying to figure out if this tower and center channel setup would work (depending on size and cost) for my girlfriend's father for Christmas. We're trying to figure out if we both could split the materials cost and me throw in some labor to see if it'd be feasible to do this for him. I sure would like to get those vinyl wrapped Klipsch's out of his system. So would his wife as she hates black speakers too! :)

dawaro

10-04-2005, 08:26 PM

Brian the dimensions for the baffle are in the first page of the thread. I will have to look around for the actual volume but I think it was 3.5ft3 tuned to 28hz.
Dennis is going to try to get the measurements done but is in the middle of dealling with the sell of his house. So we are still waiting for now...

cjd

10-04-2005, 08:45 PM

Brian: If this ends up too big the stuff I'm pondering for my own HT might fit the bill as well. Not really set on what parts to use yet but it might get interesting design-wise. I'm VERY space limited so will be going decidedly smaller than even RS225's can sneak sealed. Problem is I doubt I'll be getting to it in time for this holiday season. ;) Unless Monday's interview doesn't go so well.

C

Brian Bunge

10-04-2005, 09:18 PM

Dawaro,

Thanks for the info. I saw the baffle layout but nothing concerning the depth of the cabinet. Let me know when you find out.

Chris,

What did you have in mind? He currently has powered towers but doesn't have the subs connected to the LFE out on the receiver. He's just running them full range off the Yamaha receiver. I doubt he'd need huge bass response and might not be interested in a dedicated sub anytime soon so I'd want something that could keep up pretty well. His system isn't optomized at all so I know there's room for improvement. Your little MTM's in tower design with some sort of bass augmentation might be perfect for him. I think if you redid the XO for horizontal placement the MTM might not even sound too bad as a center.

cjd

10-04-2005, 10:50 PM

How loud do they listen? If you stay <90dB the MTM has enough bass methinks, much louder potential if there's something like a nice compact subwoofer tucked in a corner. 40Hz in room. And I even have a nifty tower option available! ;) Heck, if it's not something like Bela Fleck (anything with some SOLID bass 35Hz and down) they can get quite loud without issue!

I do have a version with the RS28A that should do much better as a center. Once this other project is done I plan to "borrow" a tweeter and whip up that crossover. I may also revise the 27TDFC version to a lower cross.

I may just do these in the HT.

I am also considering a TMWW with a pair of RS180's for bass, and a 125 (or maybe 150) and tweet. A bit more bass extension available here.

I'm also considering something with a mini TM or MTM up top and a larger "bass module" of sorts - one of my tricks is a maximum usable width of 6.5" on one side between the wall and the screen. But below about 26" up it's all open space. . .

Surround, not sure. I may even start there as I owe my dad some surrounds.

The real fun of having the measuring equipment is you can do whatever you need/want and probably find someone *somewhere* that can put together a crossover. For the $100 it cost me (well, $200 including the new sound-card). . .

May have to look into SoundEasy or LSPCad soon. :)

C

C

Brian Bunge

10-04-2005, 11:13 PM

I don't think they really listen that loud. So far, I've only experienced them using the system for music during dinner. I know he watches NASCAR in HD on the weekends and some action movies but I doubt they listen very loudly. I think 90dB would be about the limit. Hell, the only DVD's I've even seen in the house was a couple of films the younger daughter has appeared in.

They have a large, open floor plan home on a slab so only a monster sub is going to really shake the house. I don't think that's even remotely necessary though. I'd thought about a 3-way with 180's for bass duty or maybe Jon's Modula MTM in a tower design would work fine too. I think a small sub using one of the new RS 10" or 12" drivers tucked in the corner would work great for his needs if just towers aren't enough.

dawaro

10-05-2005, 12:32 AM

Brian have you looked at Roman's 3 way with the 225/125/28?
http://www.rjbaudio.com/Daedalus/daedalus.html
You might also think about the Modula MT's in a tower. For 90db they should be more than enough.
BTW the measurements of the TMWW was 17.75d x 10.75w x 42h. 3.5 ft3 with a tuning of 28hz.

cjd

10-05-2005, 10:32 AM

good suggestions dewaro. :)

Brian: I was not suggesting a sub to shake the house - I was suggesting a sub to make sure that the MTM's don't get overloaded. I suspect that with any kind of an action film with heavy bass, overexcursion could be an issue given how ported enclosures like to jump on the excursion numbers *really* fast below the tuning point. :)

C

Brian Bunge

10-05-2005, 11:15 AM

Dawaro,

Yes, I've seen Roman's 3 way. That might be a good design except I don't like the narrower, separate enclosure on top. I'd probably build it as a single enclosure the full width of the lower section, which means the XO would need to be tweaked a bit. I really need to get a decent outboard sound card so I can start taking measurements. I've already got LspCAD, a measurement mic, and a DIY mic preamp.

In your tower is there a separate sealed sub-enclosure for the RS 6"?

Chris,

I knew what you meant about the sub. I was just saying that I imagine a small sealed sub would probably be plenty. It's gotta be better than what's in those towers.

cjd

10-05-2005, 01:06 PM

Do you only have a laptop or something? If I'd known you had everything but, it woulda been cheaper for me to just buy you a sound card!

M-Audio does (or did?) have a very good outboard sound-card - theoretically available for ~$80 IIRC.

RS-10 or two in a nice little sealed enclosure would be slick!

C

Brian Bunge

10-05-2005, 01:11 PM

Yeah, laptop is it. I've got a Kim Giardin (sp?) calibrated mic with file, LspCAD 5.25 Pro (Ingemar gave me the site key for the pro version last time I changed laptops), and a battery powered mic pre that is supposed to be based on the Panny capsules that Kim uses.

I've seen the M-Audio Mobile Pre but don't know if it can also take the place of a soundcard. Maybe I should post this on the LspCAD board on Yahoo.

KJP

10-05-2005, 01:23 PM

http://www.m-audio.com/products/en_us/Transit-main.html

cjd

10-05-2005, 02:00 PM

Transit. That's the one! :)

C

Brian Bunge

10-05-2005, 03:00 PM

OK, the last question concerning this little gem. Is it full duplex? I don't see mention of it on the M-Audio website.

cjd

10-05-2005, 03:15 PM

AFAIK it is at least up to 48kHz sample rates. Haven't actually used it but I thought I had seen it being used by someone with Speaker Workshop.

C

dawaro

10-10-2005, 07:33 PM

It looks like there is going to be some serious delays in the design for the TMWW. Dennis is going through some serious issues with the sale of his house and his personal relocation so this has been put on the back burner until a later date.
Sometime in the near future I will get a better layout of the cabinet done and posted. But without the measurements I am not sure there is a real rush for it.

Brian Bunge

11-01-2005, 12:09 PM

Now that my tower cabinets are done I want to build this center before I move to Florida. I've got the MDF and veneer but no drivers (except for the tweeter) and can't really afford to spend the cash on drivers right now. So I was wondering if anyone would be willing to loan me an RS 8" and RS 6" so that I can get the baffle cut. If I can do that, I'll be able to get the cabinet done before I move and then can finish the center when I can afford to buy drivers and XO parts.

If anyone can help me out I'd make sure to ship the drivers back in perfect condition.

shaqdaddy86

12-23-2005, 05:28 PM

I was thinking to build the center channel to go with a pair of Dr K's MTM. I was wondering which crossover would be best to go with, or if this center channel would be too big to match well with the Dr K's.
Thanks
Derek

cjd

12-23-2005, 07:46 PM

Derek, I'm not sure any of these crossover designs have the response anomolies of the DrK's. ;) This is definitely a bigger speaker and will have a bigger sound, sorta. But it should match quit well with an RS28A/RS180 speaker - Jon has done both the Natalie P and the Modula with that driver set (either crossover would also drop into your existing DrK box/driver set).

I haven't noted whether Curt's updated crossover has been posted or not - if so, pick one I think - they all should do well. Dennis has proposed the simplest crossover, which will help keep costs down.

Jon's is a no-holds barred, and mine isn't far behind. Both are very similar topology.

So, you see, we're not going to give you an answer 'cause there really isn't one. :P

C

JonMarsh

12-23-2005, 08:05 PM

Yeah, you pays your money and you takes your chances- with any of these, the chances are actually going to be pretty good... ;)

~Jon

kgveteran

12-26-2005, 10:08 PM

While these examples are all theoretical can some one sum up each design and what the merits of each are.

1) Dennis Murphy
2) Curt Campbell
3) Jon Marsh

I've read the posts and I'm trying to decide where to go with these designs based on the original drawings.The twin 8's will work fine with the 100hz xover of my processor and with the bass duty off the mid the chesty male vocals will be gone.

Jim Holtz

12-27-2005, 12:22 PM

kgveteran

This really isn't a theoretical design. Dennis designed his crossover with the drivers in the actual cabinet and tweeked it just as any other design he does. I know for a fact that Dennis spends a lot of time listening to each of his designs to get them right before he signs off on it. I've also built two of Jon's designs and I can attest to his crossover designs too. Excellent! I'm not sure if Curt actually listened to this design or not but he is also a proficient crossover designer. I see no risk in building this speaker. It will far out perform any commercial speaker that costs several times it's price.

What you're proposing with a 100 Hz. crossover is really a waste of the bass capabilities this speaker is capable of. It will have a F3 of around 50 Hz. sealed. F6 should be in the low 40's. Add in a little room gain and you've got a full range center channel. Chesty vocals indicate a poorly designed crossover. This speaker will not have chesty vocals running full range.

Jim

While these examples are all theoretical can some one sum up each design and what the merits of each are.

1) Dennis Murphy
2) Curt Campbell
3) Jon Marsh

I've read the posts and I'm trying to decide where to go with these designs based on the original drawings.The twin 8's will work fine with the 100hz xover of my processor and with the bass duty off the mid the chesty male vocals will be gone.

kgveteran

12-27-2005, 10:25 PM

kgveteran

This really isn't a theoretical design. Dennis designed his crossover with the drivers in the actual cabinet and tweeked it just as any other design he does. I know for a fact that Dennis spends a lot of time listening to each of his designs to get them right before he signs off on it. I've also built two of Jon's designs and I can attest to his crossover designs too. Excellent! I'm not sure if Curt actually listened to this design or not but he is also a proficient crossover designer. I see no risk in building this speaker. It will far out perform any commercial speaker that costs several times it's price.

What you're proposing with a 100 Hz. crossover is really a waste of the bass capabilities this speaker is capable of. It will have a F3 of around 50 Hz. sealed. F6 should be in the low 40's. Add in a little room gain and you've got a full range center channel. Chesty vocals indicate a poorly designed crossover. This speaker will not have chesty vocals running full range.

Jim

Well Jim, I reread and you are correct-a-mundo. It seems Dennis not only designed it but gave a listen to the 150 all by itself to listen for problems.Non found.I'm scratching together 180.00 tonight from Santa cash and ordering the drivers.My cabinet guy will get the plans tomorrow and I'll hash out a price with him.Plain ol' MDF 3/4" type.Oh, boy...here we go. If the towers never make it to the drawing board i'll make three of these!

Curt C

12-28-2005, 12:44 AM

Sorry, I don't get out much anymore...

I'd revised this crossover some time ago, as while 1500 Hz shouldn't be any trouble for most examples of the RS28, it really didn't need to be crossed that low either. You can see the revised networks at this link:

http://www.geocities.com/cc00541/drRSWtmW_CC1800Hz.html

The tweeter now is crossed at 1800 Hz. Not much else really changed...

C

kgveteran

12-29-2005, 10:28 AM

Some xover questions:

Resistors:In order to achieve the valued resistor, multiples are needed?Which is better to bring a value down, by parallel wiring or adding together series wiring.

Capacitors: Same type of question is it better to split the value by parallel wiring or wire in series and add the values together.Do they add and subtract like resistors do when wired in series or parallel ?

Inductors: The gauge of the wire increases cost and power handling.How do I figure what gauge for the bass,mid,tweeter ? When figuring the value needed I found that multiple inductors were neede like the other parts.I got the value right in "mH" but the resistance is off.I looked to other sites and their values were off by the same amount.What to do?

Thanx guys. KG

Curt C

12-29-2005, 10:53 AM

In my designs I almost always optimize the components to the nearest standard value, so only in rare instances will you need to multiple components to obtain an odd value.

That said, you may be looking at the DCR of the inductors and thinking it is a resistor value. Just pick the inductor gauge that has that resistance and you are good to go. In some instances the inductor DCR and a series resistor are lumped together, so again, look for an inductor DCR and a standard value of resistor that sum to the indicated value.

Resistors and inductors sum the same, that is, series them for a larger value, parallel them for a smaller one. Caps are just the opposite. In general I prefer parallel connections over series, but either can work well.

C

kgveteran

12-29-2005, 02:38 PM

Curt,
Do you run the woofers in series or parallel ? KG

I've done a little scouting around and looks like i'll still be adding parts to make the numbers work.Is there a percentage I can be off with regard to values.Example if the schematic calls for a 9.5uF cap, can I use a 10uf with out too much error.

your list doesn't provide a resistance value with regards to the inductors.I just figured on the wattage they were rated at.

KG

Curt C

12-29-2005, 03:07 PM

Parallel.

I'm not sure why only one woofer shows on the network...

C

kgveteran

12-29-2005, 09:19 PM

dawaro

12-29-2005, 10:21 PM

I spoke with Dennis today and he confirmed that he plans on finishing the tower measurements and design no that Xmas has passed. He is planning on doing versions with both the RS28 and a Seas tweeter.

Stay tuned...

kgveteran

12-29-2005, 11:07 PM

Curt C

12-30-2005, 02:01 PM

Curt,
Sorry but the inductor ohm value on your sheet is missing.I found all the values on the aircore inductor page but the resistance value thing has me confused. Don't worry about over simplifying!

KG

No problem!
After I look at it in detail, I see I was amiss on a couple of values. My apologies for any confusion this may have caused you.

On the woofer net, R1011 is the DCR of L1011 which is the Erse cored inductor PE p/n 266-924 R1031 is the DCR of L1031 and should be an 18 ga Jantzen PE p/n 255-230.

Likewise on the mid net, R2021 is the DCR for L2021, R2041 is the DCR for L2041 Use Jantzen 18 ga. For these. Apparantly I didn’t ‘quite’ finish optimizing this design, as some of the values are not standard. I don’t have the capability to massage the numbers here, so plan on a 10 ufd for C2031, and I’ll post back if a 9.1 ufd looks significantly better. Use a 20 ufd and 18 ufd in parallel for C2011, and a 20 ohm and 15 ohm in series for R2061

On the tweeter net, R3021 is the DCR of L3021 and is a 20ga. Jantzen. The rest of the values are standard.

Let me know if I can answer any further questions.

C

kgveteran

12-31-2005, 04:05 PM

Curt,
What would the ohm value be for the resistors:

R1011,R1031,R2021,R2041,R3021

I believe they were replaced with the DCR values of the coils. Thanx for the recommendations on the coils.

My cabinet guy wants to do a maple veneer for a tight grain and I kinda like the dark red stain.They were very bored with the plain painted MDF sub cabinets I had them make last summer.

KG

Paul H

12-31-2005, 06:34 PM

...
What would the ohm value be for the resistors:

R1011,R1031,R2021,R2041,R3021

I believe they were replaced with the DCR values of the coils. ...
KG

The resistance values noted would appear to be the DC resistance of the inductors - no actual resistors are required in the circuits for these 'resistors' .

This software appears to require the user to insert an extra resistor at each inductor in the modelled circuit to simulate the resistance of the inductor.

Paul

kgveteran

12-31-2005, 08:30 PM

Paul,
I'm not kidding.......I understand. :) Thanx again. I've changed my mind on the sequence of purchases, I'll get the xovers done while the cabinet guy knocks out the cabinet.

KG

kgveteran

01-02-2006, 11:26 AM

Paul H

01-02-2006, 11:53 AM

Just to clear up a possible last issue.If I wanted to separate the woofers from the Mid/tweeter, I would wire the woofers to the one set of binding posts and combine the mid and tweeter to the other binding post.

Can this be done to this design without problems?

Yes it can, and provides the option of bi-wiring and bi-amping. If you later decide to run from a single amp you can just connect the binding posts at the back of the speaker.

Paul

kgveteran

01-02-2006, 03:58 PM

Thanx Paul.

Brian Bunge

01-02-2006, 10:22 PM

Yep, you can definitely do that. In fact, when I built my 3-way towers I even went so far as to use a seperate pair of binding posts for each crossover. So they have the capability of being tri-wired. My center channel cabinet will have the same capability.

JonMarsh

01-02-2006, 11:18 PM

The connector people love folks like you, Brian!

I should talk, though- M8ta's built the same way. Makes testing individual sections easier, too.

kgveteran

01-06-2006, 01:16 PM

I was wondering about the 1.8khz xover point of the tweeter, so I got with PE and they said, if the xover is at least 12db/oct you were fine. This concern came from a friend with good intentions.

It seems to be?

cjd

01-06-2006, 01:48 PM

Bah.

Plenty fine.

This tweeter can (in good form) be crossed MUCH lower than that.

Your friend needs to learn to trust the designers of these crossovers more. ;)

C

ThomasW

01-06-2006, 02:56 PM

Too many cooks spoil the soup......

Pick one designer and go with his concepts. You'll drive youself and everyone else crazy having multiple designers second guessing somone elses design.

Jon's a twice published member of the AES. And remember Jon's a geezer (I get away with say this because I'm older than he is). So he's been designing loudspeakers for ~40 yrs. There aren't many people walking the planet that have his knowledge or his IQ (think Mensa on steroids) ... ;)

kgveteran

01-06-2006, 03:58 PM

Actually it was Curts design.....enough said, I will go ahead with blind faith!

cjd

01-06-2006, 04:50 PM

At some point there must be trust.

Worst case, if things *don't* work out you have to work up a different crossover.

Box and drivers will remain unchanged.

FWIW I cross my RS28's at ~1600 and have pushed them VERY hard.

C

kgveteran

01-06-2006, 05:08 PM

You got it, I can't wait to get started. :B

cjd

01-06-2006, 05:43 PM

I understand where you're coming from too. :) It's worse for me when it's my own darned design and it just sounds bad.

You get to blame others at least!

Have fun!

kgveteran

01-08-2006, 11:18 PM

Hope to get my cabinet this week.I've decided on painting the cabinet gray like my subs, with the big .75 rounded corners.

philip_g

01-08-2006, 11:24 PM

thi should be a sticky ;)

madclown99

01-09-2006, 12:04 AM

For anyone interested in building Jon's version of the CC XO, here's a BOM. I live in Canada, so I worked it out to Candian dollars. I'm going with Madisound GE caps, Solen inductors, Dayton/Madisound resistors. Inductors will be unwound to the desired values.

It came out to $250 CAD (~208 USD) per XO. Solen parts are listed in Canadian dollars. Madisound/PE prices are listed in USD, but all subtotals/totals in the grid have been converted to CAD (exchange rate as of Jan. 8th, 2006 is 1.19).

For anyone interested, I'll be posting similar BOM for the Modula MTMs and Natalie Ps, since I'm going to build them all for a HT setup...

kgveteran

01-10-2006, 04:15 PM

All right! The order has been placed and drivers and xovers should be here by thursday.Back order on the 100uf cap.

Cabinet guy should get his check tomorrow and I'll iron out the plans with him.

Oh, boy...I can'y wait. :B

dawaro

01-11-2006, 09:44 AM

If you are going to use a 3/4" round over make sure you adjust the height of the enclosure. The original was built with 1/2" round overs and I am not sure if there is enough room to go larger without adjustments.

kgveteran

01-11-2006, 12:28 PM

I will make that adjustment.I'm not sure why I thought .75" . Thanks for keeping track of progress.I should be doing some evaluating as soon as the backordered cap comes in.

Brian Bunge

01-11-2006, 05:40 PM

Is the original height 12.5"? If so, a 3/4" roundover will work fine. I screwed up and made my cabinet 11.5"H and even with squishing the tweeter and mid as close together as possible I could only get about 1/2" deep 45 degree chamfer on the baffle top and bottom.

kgveteran

01-11-2006, 08:31 PM

I'll see what size he used on my Tumult cabinets and match them. There are a couple guys up at work that maybe interested in this center project.The projected cost of the compitition is pretty steep.

kgveteran

01-12-2006, 10:18 PM

Here are some pics of the xovers and drivers.The midrange is the big one the tweeter is the little one and,WOW, look at that coil.It weighs about 2lbs.I'm missing the 100uF cap for the 225's.That thing must be the size of a coke can.

How warm do xover parts get? I used hot glue and figured I should secure with something else in case it gets warm in there.

No doubt this speaker will weigh in at more than 85-100lbs all said and done. :)

kgveteran

01-12-2006, 10:27 PM

The coil didn't make it. :)

SteveCallas

01-12-2006, 11:25 PM

Holy crap, a 100lb WTMW center channel? When you do DIY, you sure do it right :T

kgveteran

01-12-2006, 11:57 PM

That's a guess on the weight Steve.The box weight was 30lbs.Maybe more like 65lbs.

Do you guys think I should run some pink noise to see the response and check for proper wiring for each xover.I'll use TruRta and do a close mic at low volume.

Curly Woods

01-13-2006, 10:12 AM

Landroval

01-13-2006, 10:27 AM

Shouldn't one of these inductors be placed on edge to minimize interaction?
Yes.
http://www.troelsgravesen.dk/coils.htm

kgveteran

01-13-2006, 10:42 AM

I will address this tonight.Thanx alot.The devil is in the details

kgveteran

01-13-2006, 11:11 PM

Here is the new position for the coils.What are your thoughts on the iron core inductor and the coil . I think I may just distance them instead of keeping them on the same board.

kgveteran

01-15-2006, 09:45 AM

Once the drivers arrived I began to double check the specs on the cabinet before dropping the plans off to the cabinet guy and one small issue came up.

The hole for the tweeter on the blueprint is 3.25".After measuring the tweeter I found the magnet structure was 3.0". I think the terminals sticking out is why that got bumped out .250".I am going with a smaller hole so I have more to bite into when I make drill holes for mounting.

I hope this isn't going to be my RS blog :oops:

I checked out the tweeter and midrange using TruRta and pink noise.They look great.The mid lacked a little bit in the bass, but thats probably because it was tested in free air.So far so good :T

Brian Bunge

01-15-2006, 04:39 PM

I think I made mine 3 1/8" diameter and also drilled out 1/2" diameter holes where the terminals were located. I think I cut out the hole at 3.25" on my towers and there was barely enough MDF left for the mounting screws to bite into.

kgveteran

01-18-2006, 08:30 PM

Here is the cabinet.I have to thank the guys at Chesis Woodwork Rochester NY.They did a great job.Acouple notes.I will be opening the midrange cutout so the sound isn't squeezed through the little gap.Iwould suggest the next cabinet have a 3/4" larger opening in the second layer of MDF.

For some reason, when the camera comes out my son has to pose.

Dennis H

01-18-2006, 08:54 PM

Lookin' good KG. If you have one, set a jigsaw at 45 degrees and slow speed and it's pretty easy (be careful!) to relieve the back side. I'd do it for the woofers as well as the mid. If you can't or don't want to do it yourself, the guys at the cabinet shop should be able to do it in a couple of minutes. They probably have better tools and more practice so that might be a good way to go.

Brian Bunge

01-18-2006, 09:55 PM

I've also seen roundover bits that can actually round the backside of the hole from the front side. From what I remember, they weren't exactly cheap though.

kgveteran

01-18-2006, 10:33 PM

I'll make a little redo list for the guys. I definitely want three of these for the front. I'm waiting for my 100uF cap to come from Zalytron.I have a few days to get this done.

ssabripo

01-18-2006, 11:13 PM

Looking good kg....you are making this tempting for me!

btw, did you see the pm I sent you over at avs? I'm dying to see that info.....;)

dawaro

01-19-2006, 01:12 PM

It has been brought to my attention that the depth of the enclosure on the drawing in the original post is incorrect. It should be 16" and not 12". Hopefully this won't cause any major problems although it does raise the Q to .85 instead of .707. Right now I am going through a PC rebuild but as soon as I have access to the files I will make the correction.

Jim Holtz

01-19-2006, 02:48 PM

Hi David,

I was one of the individuals scratching my head trying to figure out how you came up with the box sizes. :) I'm curious what you're using to calculate the box sizes for the RS225's? I'm using Unibox and I come up with about 53 liters for (2) RS225's at a box Q of .707. What are you coming up with?

Thanks for getting the ball rolling on this design. I think it'll make a superb speaker. :T

Jim

It has been brought to my attention that the depth of the enclosure on the drawing in the original post is incorrect. It should be 16" and not 12". Hopefully this won't cause any major problems although it does raise the Q to .85 instead of .707. Right now I am going through a PC rebuild but as soon as I have access to the files I will make the correction.

cjd

01-19-2006, 03:18 PM

Jim, are you accounting for the additional series impedance of the crossover components, etc? Of course, I don't have these drivers loaded into Unibox here so I'm not running the numbers myself, but that's the first reason I can think of for some disparity. Also, of course, the differences in how much you're assuming the drivers themselves take up volume-wise inside the box.

In this case, if memory serves he's doing everything right. :)

C

dawaro

01-19-2006, 04:15 PM

Jim is right. I ran the numbers after he e-mailed me. (By the way my PC crashed before I could respond to it.)
53l is the correct volume for a .707, with the 12" depth it comes up at .85 IIRC.
So far KG is the only one that I know of that has built an enclosure and the smaller size should not hurt him. He is really not concerned with any thing below 80hz and actually wanted the enclosue smaller.

dawaro

01-19-2006, 04:31 PM

KG - You might be able to use a bit like this to roundover the inside of the cabinet.
Price Cutter Bit (http://www.pricecutter.com/product.asp_Q_pn_E_P14%2D3128)

The cutters are adjustable so you can move the top cutter to clear the baffle and just use the bottom cutter, the top may even be removable.

You may also use a dovetail bit with a top bearing like this-
CMT Dovetail (http://www.sommerfeldtools.com/products.asp?id=55)

kgveteran

01-19-2006, 05:29 PM

Thanx for all the input (excuse the pun ).It's nice to know that no one gets left behind in a DIY project.So far at every turn I have had great support.

My first thought was that a smaller cabinet would get me closer to my processors xover frequency.With that said it reminded me of the THX class I had a million years ago.They had talked about the 80hz xover.If the speaker had acoustic rolloff @ 80hz and an electronic xover @ 80hz it would match the 24db/oct hipass on the sub.I guess that would create more problems with a hole around the 80hz range so an F3 at 53hz is no probem at all.

Tonight i'll start to tweak the cabinet and hopefully my xover parts come in today or tomorrow.

KG

Edit: Here are some pics One shows the 1.5" thick baffle of the 8" woofer and the other shows the reduced interior baffle back for the midwoofer.I used a router bit very extended.It cut away about a 1/4" deep and 1" in lenth and the rest I got down with a shoe rasp.The big cap came in so the xover work is done.

Jim Holtz

01-19-2006, 10:11 PM

Whew! Thanks for responding David. I just couldn't get the numbers to come out right and I was trying to figure out what I was doing wrong. I'm glad i wasn't goofy. :-) This will be a very nice project. I hope things are going well and you've recovered from Katrina.

Best regards,

Jim

Jim is right. I ran the numbers after he e-mailed me. (By the way my PC crashed before I could respond to it.)
53l is the correct volume for a .707, with the 12" depth it comes up at .85 IIRC.
So far KG is the only one that I know of that has built an enclosure and the smaller size should not hurt him. He is really not concerned with any thing below 80hz and actually wanted the enclosue smaller.

Brian Bunge

01-19-2006, 10:17 PM

I was scratching my head on the 12" depth as well. I went ahead and adjusted the volumn on my own for my center. IIRC, I went with 62L before subtracting for the midrange enclosure. I think I ended up somewhere around 55L.

Jim Holtz

01-20-2006, 12:08 PM

I'm looking for a small MTM center for my Son. I noticed your project and wondered if you could give me some information about it. It looks like RS150's/27TDFC which would be a prefect match to the Modula M/T's I built for him. Jon's Modula center is too big and too expensive.

Thanks!

Jim

How's this?

http://www.eldamar.net/audio/rs150mtm/graphics/P0000519.jpg

Minwax Ebony stain on Birch.

Can be laid down lighter, but it takes on an ever more brown (still very rich and dark) hue.

C

cjd

01-20-2006, 01:56 PM

Uh, Jim? You've heard this one. It just wasn't on its side. :) And, you know, there were a pair of 'em.

Just updated with a lowered crossover for the TDFC (since my FTP access was fixed).

RS150 MTM (http://www.eldamar.net/audio/rs150mtm/)

Jim Holtz

01-20-2006, 02:32 PM

Chris,

I thought that it might be the same as the design you brought to Chicago but I wanted to see if you'd done a special version as a center. Now, I need to figure out if the tweeter needs to be shielded for my son's use or not. I'd prefer to stay with the 27TDFC if possibe. I like that tweeter.

Thanks for responding.

Jim

Uh, Jim? You've heard this one. It just wasn't on its side. :) And, you know, there were a pair of 'em.

Just updated with a lowered crossover for the TDFC (since my FTP access was fixed).

RS150 MTM (http://www.eldamar.net/audio/rs150mtm/)

cjd

01-20-2006, 03:02 PM

Part of the design goal of that one was a crossover that worked well both vertically and horizontally. It is targeted at the DIYer that's limited by reality (i.e. near-wall placement, fitting around furniture), no monster boxes way out in a room with a single chair and nice acoustic treatments...)

It also works well with either version of the Seas 27TDFC (the shielded version drops right in, though it may have a bit more "BBC dip").

In fact, the version posted in this thread has the shielded tweeter as it was a gift for my sister, and it sits next to her TV. :)

C

kgveteran

01-21-2006, 12:01 AM

I couldn't wait to get a pic of the drivers mounted.I need to get the cabinet back to the guys at Chessis for a little larger route out on the 225's.

Here's the xovers.I repositioned the two coils as advised on the midrange board and added some extra wire to the 4.7mH choke to keep it away from everyone.Check out the size of that 100uF cap.

Since the magnets are shielded, does this add any benifit to motor assembly not interacting with the xover parts?

Edit: I made a jig and widened the 225's recess.I'm painting now and trying to figure out what to use as binding post.I like the brushed aluminum dual plate with the brushed aluminum posts.Parts express of course.

kgveteran

01-22-2006, 10:47 AM

I ordered the brushed aluminum terminal plate with two sets of satin binding posts to biamp.

Cost so far: Drivers 164.00
Xover parts 78.00
Cabinet 125.00
Terminals 37.00

404.00

You can drop that price by knocking the cabinet out yourself and saving about 75.00.That would cover the xover parts if you choose Curt's design.

Edit:Here is a finished pic.Check out those drivers.Pretty cool :T

dawaro

01-22-2006, 05:11 PM

Ok since Dennis is close to being complete on the towers here are some details for the tower construction.
The design for the RS225's is 3.5ft3 ported to 26hz with a f3 of 30.2hz. The RS150 is in a 5 liter sealed enclosure. The cabinet is constructed out of .75" mdf with the front baffle doubled up for 1.5". The front baffle edges have a .5" round over.
I have attached a couple of layout drawings to help with the construction.
If there are any questions or more importantly ERRORS, let me know.

David

kgveteran

01-23-2006, 01:04 PM

Quick xover question.Did I waste 20.00 on a metalized cap (100uF).Could I have gotten away with an electolytic cap instead.Thanx.

cjd

01-23-2006, 01:23 PM

You did not waste money (though you could have saved some by going with a big bundle of the 10's from madisound if you buy enough).

You *could* use electrolytic, but... well,... I wouldn't. I would at the most look to a more budget oriented metallized poly cap - Bennic or PE's house caps, for example.

:)

C

kgveteran

01-23-2006, 04:38 PM

dawaro

01-23-2006, 11:00 PM

Ok, for those that are interested in the measurement files for the tower I have them but my personal site is down right now so I can not host them. If you want them send me a PM and I will e-mail them to you. I am going to send a set to Jon, Curt, and Chris.

David

AJ Bertelson

01-25-2006, 12:19 AM

Dawaro,

What would recomened for the distance of the rear of the speaker to the wall since it is a ported design?

dawaro

01-25-2006, 09:57 AM

Being that they were designed for HT use I would think having them 12" or so from the wall would be ok but I will ask Dennis how he had them set up when he did the measurements and voicing.

cjd

01-25-2006, 10:52 AM

Oh boy. Since I got a little more info this time around (or failed to read it or at least fully understand it last time?) I may have to revise my previous crossover... I think I misinterpreted how the measurements were done. That, or I have forgotten completely how I went about this before. :P Either way, will take a look at it. At least I'm not aware that anyone has bothered with the stuff I posted.

C

Brian Bunge

01-25-2006, 11:49 AM

Stayed home sick today, thanks to a nice upper respiratory infection, and Mr. UPS brought me a present. I got back my baffle and back for my center channel from Pete Mazz. Except now they are gloss black! They look awesome!

If I feel up to it later today I may try to snap a few pics of them and post here.

Thanks again Pete!

kgveteran

01-25-2006, 10:40 PM

Well she's up and running :T . I took a screen shot (via my camera :oops: ).It was a close mic pink noise and all looked good.I little peak at about 200hz , but in the grand scheme thats small.

What I noticed was how clear Dave Mathew was on "Dream Girl" (Week end at the rocks DVD). I'm use to the voice loosing it when the volume got up there.Twoways do that.The mid range is clear and the tweeter seems fine with everything.

I'm sure there will be some relaxing once I get some breakin time going.Seems to run very clean on the 100watt side of my B&K ST-140.

Edit: I also listened to Keb' Mo' Sessions at west 54th.I lowered the center xover to 80hz.This is a great DVD.Sounded super.I know I keep saying how clear it is, but it is very clear.No chesty sounds.I want two more :B .

dawaro

01-26-2006, 12:32 AM

Glad to hear you are enjoying the speaker. Looking forward to the towers now?

kgveteran

01-26-2006, 06:47 AM

No doubt :D .

Jim Holtz

01-26-2006, 07:12 AM

Edit: I also listened to Keb' Mo' Sessions at west 54th.I lowered the center xover to 80hz.This is a great DVD.Sounded super.I know I keep saying how clear it is, but it is very clear.No chesty sounds.I want two more :B .

Just for fun, get wild and crazy. Try running the center full range and listen a while. :) RS225's are known for lots of clean tight bass.

Jim

cjd

01-26-2006, 11:02 AM

Two things...

Get something to hold the mic that isn't going to be reflecting lots back. :P

And, drop the crossover to 60Hz. After listening full range, that is.

C

kgveteran

01-26-2006, 01:14 PM

I'm thinking that 60hz is closer to the units lower limit and may be a better blend with the subs.

I'm planning on listening to some Diana Krall (SACD) tonight.I'm sure this is going to be a great breakin period.I've also got some Steely Dan in DVD-Audio to listen.

I know you guys are hot on the towers , I may make two more of these.They are such a perfect match for what I need.

Howabout some rear surrounds?

cjd

01-26-2006, 01:23 PM

ssabripo

01-26-2006, 01:37 PM

Well,

given KG's success, and given my hardship trying to come up with some good XO's for the Seas based center I was planning on, I may actually copy this design....

so my question would be, how would the Dayton RS Towers compare in SQ to the Seas Thor replicas? I really love the simplicity and details of the Thors, but if I go with this Center, I would like to match the fronts as well...

:huh:

kgveteran

01-26-2006, 02:29 PM

towers are just practical for most of us. :)

Things will change in surprising ways when you have a whole front stage of these suckers.

Surrounds... ahh, so many projects to do...

Modula MT, even my MTM, both existing and reasonable options for surround duty I think. Heck, you could go Natalie P too. :) Part of the question is how much space do you have for them. And how soon do you want 'em. :)

I have a couple pieces of furniture to build before I get to any more projects, but aside from the fun whacky project redoing my HT is up there. I'll be looking at some ceiling/wall corner mounted surround options for this.

C

My room is about 13.5 x 15.5 x 9 . Can't wait to get the fronts done. I'm suprised at how well my little B&K powered the center.it had the same SPL as the paradigm twoway I was using as my center.

My plans are to power each LCR with one B&K ST-140.One side for the 225's and one side for the 150&28a.I'll then go pick up a three ch. B&K to power the sides and rear center.

This has been a real pleasure to build this speaker with great results and lots of help :T .

How would you guys rate this in difficulty ? From 0 -10 .

Landroval

01-26-2006, 02:29 PM

Modula MT, even my MTM, both existing and reasonable options for surround duty I think. Heck, you could go Natalie P too. :) Part of the question is how much space do you have for them. And how soon do you want 'em. :)
I dont know if there's one already, but a no-BSC version of either MT or MTM would be nice for wall mount situations.

Paul O'Neal's RS150+RS28 could also be fine.

kgveteran

01-26-2006, 02:36 PM

I dont know if there's one already, but a no-BSC version of either MT or MTM would be nice for wall mount situations.

Paul O'Neal's RS150+RS28 could also be fine.

I can find paul O'neal's 150-28a.........where? That sounds like a perfect match for a rear(side) surround.This is a very dangerous forum :) .

Landroval

01-26-2006, 02:49 PM

Here:
http://home.stx.rr.com/poneal/index.html?Page=Speakers

There's discussion about it at PE Tech Talk (haven't read it though).

kgveteran

01-26-2006, 04:23 PM

Perfect. :T

cjd

01-26-2006, 04:47 PM

I have a low BSC version with the 28A tweet posted. RS150/RS28A MTM. The only difference with Paul's (generically) and mine is the extra power handling and to some degree extra sensitivity of the MTM (ignoring the fact that I used two Rs150's, he used one).

C

kgveteran

01-26-2006, 10:43 PM

BSC ?

Paul H

01-26-2006, 10:46 PM

BSC ?

Baffle Step Compensation

Paul

cjd

01-26-2006, 11:36 PM

More BSC is needed when the speaker is placed "out in the open," less when it's placed up against a wall. :)

C

Landroval

01-27-2006, 01:16 AM

http://www.t-linespeakers.org/tech/bafflestep/index.html

"At high frequencies, a loudspeaker tends to project sound only in the forward direction that is, it has a 2 pi hemispherical radiation. At low frequencies, a loudspeaker undergoes a transition by which it begins to radiate sound in all directions, or a 4 pi spherical radiation. The result is an apparent reduction of bass response because the low frequency energy density is reduced in the forward direction where the listener is located. The overall effect is a gradual 6 dB shelving action at low frequencies, such that the bass is 6dB lower in level than the treble."

kgveteran

01-27-2006, 12:56 PM

I have to give myself a pat on the back here, I understand what you said! Hence the house curve on some subwoofer installs.

BTW, I sold off an older pair of Paradigms....do you think the cabinet guy got a call this morning? Of course :B .

I would love to get a set of plans on the sealed dual(side or rear surrounds) 150's and a 28a. I think this will turn into a RS HT system thread. :T

cjd

01-27-2006, 02:11 PM

You want MTM with RS150/RS28A?

http://www.eldamar.net/audio/rs150mtm/

http://www.eldamar.net/audio/rs150mtm/graphics/enclosureDesign.gif

I am going to be doing a review of the networks I have posted here again - I think that you'll not want to use the shielded tweeter, and I only have a low(er) BSC version posted for use with that tweet. If this is what you want I will make a point of putting that together for you. :)

If this cabinet shape isn't quite going to work, I think I can work up some other options as well. May even toss together a test baffle and run some measurements. :)

C

ssabripo

01-27-2006, 03:38 PM

KG,

so what's the feedback thus far? I'm waiting to hear from you to decide whether to go with this proven and cheaper solution, or go ahead with the more complicated and expensive Seas Excel based center....

:p

kgveteran

01-27-2006, 04:40 PM

I've written a couple lines here and there, but for the most part this center channel will play so clean at my usual listening level (80-85db (with a 80hz XO) that I will never need another.

My theory on using this design (as well as my subwoofer system ) was to have lotz of headroom. The mid has the room to provide very clear* sound at the level I listen.

clear* One problem with a center of this quality is that I will no longer get that glazed over sound quality.I'm going to hear the sound track under a microscope now.This will only be a problem when listening to poorly created soundtracks.I played a couple of scenes from WOTW and it sailed along with little to do but shell out the dialog.

I can't even begin to tell you the cost/value ratio. You have to look around to see what is available in that price range.

Once again, tons of props to the guys who design XO's and blueprints, so semi-DIY guys like me ( you know, guys who have a cabinet maker do their speaker cab's ) can walk away with a real shining example of dedication :T

ssabripo

01-27-2006, 04:53 PM

cjd

01-27-2006, 06:08 PM

so you are saying I should stick with a Seas based CC? :B http://www.99smiles.com/mamoru.gif

Though I do believe you are making a joke here... just to be sure, the Seas will be just as detailed. :)

The RS drivers stack up way to well against the Seas drivers for their price. Well, only too well for Seas. Great for us!

C

kgveteran

01-27-2006, 09:19 PM

grab a bunch of the RS28a drivers for 37.00 each too.Sure, knock yourself out.

You have to figure on what you need.What are you looking for in a center design?

ssabripo

01-27-2006, 10:44 PM

grab a bunch of the RS28a drivers for 37.00 each too.Sure, knock yourself out.

You have to figure on what you need.What are you looking for in a center design?

oh, not looking for anything special really.......just a KICK@ss Center, that will run clean and powerful at refernce levels, with outstanding depth perception and voice detail and imaging, for relatively cheap :B :T

is that too much too ask?

ps- I'm leaning towards you design to be honest...the seas, although some of the best drivers, are also much more expensive, and require really accurate XO's. The only thing is, I'm gonna do a variation on it....not as high, but a little wider and deeper to compensate for the equivalent Volume.

I'm hoping Curt C will chime in and tell me if there is a need for changing the XO design slightly to accomodate this mod in dimensions. I wanna go from 12.5" in height to 10.5-11" at most.

cjd

01-27-2006, 10:53 PM

kgveteran

01-27-2006, 11:07 PM

cjd,
I went with Curts' XO redesign on the 4th page ,I think. I liked the 1.8khz on the 28a. Not knowing alot of the details, I chose one and ran.

I've been using 300.00 paradigm MiniMK3's for my LCR.To go from that to this monster was the hugest step up.The mini's held up to about 85db, and thats when the cone movement prevented proper midrange articulation.If there was a way to mod the Mini and add a 8" woofer with a 400hz XO I'd a done it.I had to up grade to play at that level and absorb the peaks with headroom.

PS. Here is a shot of the final resting place, and how about that Dayton brushed aluminum plate and binding post.They realy let you crank down, unlike the plastic jobs that spin loose
S,
What are you using now for mains?

ssabripo

01-27-2006, 11:08 PM

I thought Dennis's crossover was used by kge? Not sure. :) 11" should work out well enough - the trick will be trying to get roundover similar. Use of felt will help a lot, and may be more useful in your case pushing the height and probably limiting roundover/edge-treatment. That's my thoughts on the subject, and others can chime in. :) You may want to post that Q in the original thread.

You're not going to get any imaging out of center channel - that's a function of a multi-speaker setup. :P If your mains don't match it will hurt the total imaging ability of your front setup somewhat - your ears are better than you think at noting sonic differences when there shouldn't be a difference. That said, the RS stuff *can* image superbly. That was one of the things folks commented about regarding my budget category RS150 based MTM's (they also won that category...) :)

And my big towers image way too well for the very poor room location they get. Staging is very good as well.

It's in the design as much as anything. And the RS drivers take as much attention as Seas.

I would be VERY much surprised if one of the RS CC concepts wouldn't be just the ticket. I'm about to embark on redoing my HT with them, and it's not an issue of budget for me at this point. My HT is too small for the RS150/RS225 based setup you're looking at.

C

Thanks C....I also hope others chime in as well.

I am getting more and more sold on doing the Dayton RS Center channel like kgveteran, but with a slight twist:

I have a height constraint of max 11", so I would like to keep the height between 10.5-11" max! The Tweeter and the mid would be side by side vertically, with the tweeter flush mounted and the mid surface mounted (perhaps with a slight overlap as well) as discussed here:
http://www.zaphaudio.com/mtg-surface.html

The only question is this:
will I need to modify your XO? If not, I think it is a done deal....hopefully I can get some answers.

:T

ssabripo

01-27-2006, 11:24 PM

....
S,
What are you using now for mains?

Swan Diva 6.1's at the moment:

http://server4.ihostphotos.com/img/16458.jpg
http://server4.ihostphotos.com/img/16459.jpg

They use the Hi-vi drivers and XO's...they are superb for what they are: commercial Internet retail speakers, just like Axiom and Rockets.

I will be probably swaping them to the 6.2s, which also use a brand new Hi-vi mid and woofer (got that opportunity to swap them as a beta tester):

http://www.kelvinphoto.com/swan6.2f/slides/ME6N9528.JPG
http://www.kelvinphoto.com/swan6.2f/slides/ME6N9526.JPG

But at the end of the day (probably by summer or fall), I would like to have my own DIY set, and thus, the project will start with the Center Channel.....I was really REALLY set on doing the Fat THor's as my Mains in the next few months....but the Seas Based Center is a getting to be a PITA. The Selah audio design is gonna cost me around $1k with materials, etc. :(

So, Now I'm kinda debating a few things:

1. If I do this RS center, which I'm really leaning towards, how well will they match to the Swans? that remains to be seen. Down the road, if I still go with the Fat Thors, how will it match with those?

2. If it doesn't match well, then I may be forced to sell it and start over with the THors and the seas....OR

3. Just either keep the swan 6.2's or go with the Dayton RS towers....

my heart is set on the THors, but that Center is just killing the whole thing...plus, seeing how successful your Center went, and how good it looks, at more than half the price, I am really reconsidering the whole thing and going with that instead.

heck, I guess I could just be a hard head, and do the Dayton RS center, and still go with the Thors....give up a little of the balance and mesh of having the same drivers but have what you want...almost

ssabripo

01-27-2006, 11:35 PM

Brian Bunge

01-28-2006, 02:30 AM

Have you ever heard the Thors? I did, twice. Both times they sounded lifeless and dull. Of course, the first time was the day after assembly was completed so no break-in time. The second time, I think there was an XO issue. I guess it could have been the lack of bass due to the less than ideal cabinet size. I'm really not sure.

I'd put my 3-way towers up against the Thor any day of the week (thanks to cjd, that is!). I've finish my 3-way center and am still not sure which design I should go with. I believe Chris was going to re-visit his design and if he thinks it'll be a good match for the 3-ways I may go with that. If not, it'll probably be Curt's since he's done some designs for me in the past that came out great.

I think if I were you I would just go with one of the 3-way center and tower variations and be done with it. That's probably what I will do for my girlfriend's dad later this year if I can spring for the cost. Otherwise, I'll probably go with Chris' MTM design with the 150's and RS28a for the front three speakers.

Landroval

01-28-2006, 06:41 AM

I have a height constraint of max 11", so I would like to keep the height between 10.5-11" max! The Tweeter and the mid would be side by side vertically, with the tweeter flush mounted and the mid surface mounted (perhaps with a slight overlap as well) as discussed here:
http://www.zaphaudio.com/mtg-surface.html
The 11" height wont be a problem, but you should never put the T and M vertically side by side. They really should be placed the way they are. I also dont see any reason not to flush mount the mid. You should keep the driver distances as close as possible to the original design.

Your TV-stand will be a problem. You should never place a speaker in such place. The large front panel will totally mess up with the BSC point, and the shelves will give you ugly diffractions. You would get a much bigger increase in sound quality by getting rid of the stand and finding a way to mount the center so that it's in an open space the way your mains are. kgv's mount looks very good in that matter.

If I'd be you I'd build the RS-center and then give some thought to acoustics in your room.

Landroval

01-28-2006, 06:49 AM

any links to the XO parts?
Jon's design:
http://www.htguide.com/forum/showpost.php4?p=195019&postcount=87

Parts for Jon's design:
http://www.htguide.com/forum/attachment.php4?attachmentid=5287

dawaro

01-28-2006, 09:26 AM

Or you could take the money you will be saving by using the RS design and buy a stand that will accomidate the center. I have a friend that has a TV stand like yours and he used the Audax HT center that is almost the same size as the RS center. We put the speaker on the top of the stand and built another shelf above it for the TV. It worked out pretty well.

kgveteran

01-28-2006, 09:57 AM

One more thing....can you guys confirm these parts, and also show me what exact XO components where used (*cough* kgveteran *cough*):

Dayton RS225:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-366

Dayton RS28a (non-shielded):
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=275-130

Dayton RS150:
http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=295-362

Dayton double binded posts:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=091-610

and obviously the terminal ends...

any links to the XO parts?

All seems well as far as this list.All the components are at PE.I used a 20uF and a 18uf paralell for the 38uF in the mid XO and I used a 25ohm and a 10ohm to get the 35ohm also in the mid XO.

I compiled a journal that has all the blueprints and printed pages from PE and notes so I can look back to double check anything that comes up.Do some hand drawings to be sure you understand everything.Check the post on coil layouts and how inductors interact with one another.I also printed pages of important information on the forum to keep track of everything.

PE won't have 100uF caps (225 XO) for a while .I went to Zalytron and got one for 20.00 shipped.It's an Aeon I think.Metalized Poly.

The journal will help you from step to step and act as an owners manual for future reference.Keep all your receipts in it incase someone else wants to build one.

ssabripo

01-28-2006, 11:01 AM

The 11" height wont be a problem, but you should never put the T and M vertically side by side. They really should be placed the way they are. I also dont see any reason not to flush mount the mid. You should keep the driver distances as close as possible to the original design.

Your TV-stand will be a problem. You should never place a speaker in such place. The large front panel will totally mess up with the BSC point, and the shelves will give you ugly diffractions. You would get a much bigger increase in sound quality by getting rid of the stand and finding a way to mount the center so that it's in an open space the way your mains are. kgv's mount looks very good in that matter.

If I'd be you I'd build the RS-center and then give some thought to acoustics in your room.

I do agree with you to a point...the location is not the best location, but unfortunately (as you can see from the pics) I have to share this room with the kids :p: I have no alternatives, other than putting it on top of the TV (which the wife will veto) or put it on its own stand like KG, sticking out in front, which will be an eye sore to my wife, and a sure tempation for my kids to poke at it and bend the woofers cone :cry:

So, I'm either stuck with trying to fit it where it is, or do a complete redo of the system, get a new stand, possibly a new TV (I just upgraded from the 55" XS LCD, to the 60" XBR SXRD...I'm still in the 30 days in case I need to return) which would mean going to a worst resolution and PQ as there is nothing out there under 10K that will match the XBR SXRD's picture quality.

I know the stand will cause some interference with the center, and cause it sound worst than it should, but I dont know how much worst.....5%, 10%, 40%...who knows.

the point is, if the RS center would be a 50% increase in SQ, but if I lose, say 10% of performance due to the stand, then I'm still ahead 40%, right?

Landroval

01-28-2006, 11:45 AM

I would have to say that 50% of SQ comes from acoustics, the room, placement, walls etc. ~35% comes from speakers and the rest from the electronics, amps, players.

I agree with you that there are not many optional places for the center in your system, so maybe you'll just have to live with it. At least the RS-center is sealed and does not have any backfiring reflex ports.

cjd

01-28-2006, 12:45 PM

Brian: I went over the stuff I had and modeled a couple of the other crossovers and verified that mine should be good to go. It is only my memory of what I took into account that was forgetting, not things done. You may even have a nice pile of extra caps from the 3-ways to use here :). And, as always, I'm quite open to feedback and tweaking as a result of it.

ssabripo: Should probably reiterate because it's important: Keep the TM vertically oriented! If you have your heart set on the big Thors AND you find this CC to be a snug fit, you may be more interested in my as yet un-started HT redesign - it won't have the brute bass extension you get out of the RS225's sealed, but if you port it'll be quite good still. And, since it looks like I'll be using RS180's for the woofer, it will make for a very slick TL, except it won't be compromised like the Thor (which has far less volume than it should have - something I have heard a couple times to cause the sound to become constrained and less open and full).

And, you *are* going to find that you have issues with boomy-ish bass placing a CC in that spot where it's designed per Dennis's measurements. I often find that simply going with smaller gauge inductors can be a quick-fix for much of this (increase impedance) BUT this only works well if you have a sealed enclosure. Give it some extra volume because the Q will be tweaked still.

Landroval: While I agree that placement and room can have a HUGE impact on things, I find that it is still less critical overall than crossover and overall design, which is more critical than drivers used. A badly crossed speaker in a perfect room will still sound bad. A very good speaker in a bad room will still sound good. Unless my room is, by some crazy luck of craziness, far better than it should be. ;) BUT. Near-wall and/or under-TV placement when that isn't accounted for certainly WILL bloat the bass some. I do have that issue - I've compromised on sound and being able to walk in the room still, but it's the point where it no longer sounds horrible (mushy and loose) - its' just a bit excessive.

C

ssabripo

01-28-2006, 01:36 PM

ssabripo: Should probably reiterate because it's important: Keep the TM vertically oriented!
Yes, of course! when I meant side by side, I meant to say it vertically (one stacked directly above the other, not from left to right)

If you have your heart set on the big Thors AND you find this CC to be a snug fit, you may be more interested in my as yet un-started HT redesign - it won't have the brute bass extension you get out of the RS225's sealed, but if you port it'll be quite good still. And, since it looks like I'll be using RS180's for the woofer, it will make for a very slick TL, except it won't be compromised like the Thor (which has far less volume than it should have - something I have heard a couple times to cause the sound to become constrained and less open and full).
I'm listening.....!!:T
I did (do) have my heart set on the FAT THOR (not the original D'Apolito design) which is supposed to have much more openess, more bass, very full sound with good depth and sound staging.....obviously I have not heard it, but the guys over at DIYAudio swear this is the best thing since sliced bread....here is the link:
Fat Thor design (http://www.diyaudio.com/forums/showthread.php?postid=744315#post744315)

I also like the simplistic look and contemporary finish of it, with the MTM design. Finished with Rosewood veneer to match my subs, and it would look really nice.....
But, I'm all ears for your design...give me some more info on it! Obviously going to the smaller rs180's minimize the size, and would definitetly be something I could highly consider, for SURE!

And, you *are* going to find that you have issues with boomy-ish bass placing a CC in that spot where it's designed per Dennis's measurements. I often find that simply going with smaller gauge inductors can be a quick-fix for much of this (increase impedance) BUT this only works well if you have a sealed enclosure. Give it some extra volume because the Q will be tweaked still.
I dont mind a touch of boominess in the CC...but I dont want it to dillute the purity of what it is supposed to do: voice reproduction at its best, and good imaging into the mains.

Again, my concern is with lowering the height, to minimally impact the acoustical signature of the CC....This is what I dont know.

Landroval: While I agree that placement and room can have a HUGE impact on things, I find that it is still less critical overall than crossover and overall design, which is more critical than drivers used. A badly crossed speaker in a perfect room will still sound bad. A very good speaker in a bad room will still sound good. Unless my room is, by some crazy luck of craziness, far better than it should be. ;) BUT. Near-wall and/or under-TV placement when that isn't accounted for certainly WILL bloat the bass some. I do have that issue - I've compromised on sound and being able to walk in the room still, but it's the point where it no longer sounds horrible (mushy and loose) - its' just a bit excessive.

C

I agree....

Landroval

01-28-2006, 01:43 PM

A very good speaker in a bad room will still sound good.
I strongly disagree on this. It's very easy to make a $100000 system sound bad if there's no thought at all give to room acoustics. It could easily be bettered with a system where $5000 is spent on acoustics and $5000 on speakers and amps. I'm not kidding here.

Of cource in most cases the rooms are not that bad. You have stuffed furniture, bookshelfs, cats, dogs, curtains, carpets etc to help with the situation.

cjd

01-28-2006, 01:58 PM

Landroval: You're still talking systems that aren't compromised, just less expensive. A measure I don't find holds too much value overall in measuring system capability. :) If you just take that much money and put drivers together randomly, it could sound horrible or it could sound top notch, and it's all down to the crossover and implementation. Same drivers, different result. Fixing the room won't fix a bad implementation.

For example, I have a pair of speakers that cost me ~$10 to put together. They have no bass at all of course, using a 4" driver open baffle. Yet, two years ago, they were the bar by which a great many things were measured as we moved up in expense - it wasn't until we hit some of Krutke's higher end designs that some of the things those little $10 speakers managed so well showed up again.

Now, those speakers happen to sound great in just about any situation as long as they're within their output range. Nearfield as computer monitors, they're just sweet sound.

And as you pointed out, most rooms aren't a total loss - they're just not ideal. :)

I think we may actually agree and are just using different reference points. :)

C

Brian Bunge

01-28-2006, 02:33 PM

Actually, the RS180 is slightly larger than the W18 driver used in the Thors. They are both listed as 7" woofers, with the RS driver being slightly over 7" in diameter and the W18 slightly under. I'd imagine their Sd's are similar. The RS has 1mm more Xmax than the Seas and was shown through testing to have cleaner output, lower distortion below 100Hz than the Seas (or was that a comparison of the 8" drivers?). So I would expect the RS180 to hold up very well against the W18.

So if you want a 2-way MTM tower I think you'd be very happy with Jon's Modula MTM built as a TL. And you'd save a helluva lot of money in the process. I can't imagine that if there is any difference between the Seas and Jon's Modula it'll be anywhere near the difference in price of the two.

Chris: I'm very interested in seeing what you come up with for your new HT setup. I think some small footprint towers (at least width-wise) could be a real hit. Are you talking 3-way design here? The more speakers I've built, the more towers make sense to me. I've built several monitors with matching stands, and towers aren't any more work than a monitor and stand. Just seal off the lower section of the tower to match the requirements of a monitor if necessary.

ssabripo

01-28-2006, 03:58 PM

I read the thread on jon's modula MTM, but slightly confused:

what's the final XO design for it?
where are the cabinet Dwgs and dimensions?
Looks like the port is pointing down, if so how come nobody is elevating it enough to allow air flow? or am I just blind and it is a sealed design?

The first few pages talked about using the Seas "baby" millenium tweeter....is that the case or did it move to a Dayton RS8a?

any links are appreciated....

ThomasW

01-28-2006, 04:27 PM

I read the thread on jon's modula MTM, but slightly confused: Everything current is contained in Jon's first post. It's been continuously updated since the day the thread began.

kgveteran

01-28-2006, 05:05 PM

I wish my subs weren't so close to the centers' location.I get a very flat response with a close mic on TruRta.At the listening position there is a little tubby-ness on vocals.This is not what I heard in my old twoways.That was distortion.I'm sure I'll find a spot here or there and finally EQ out the problem.Which EQ to use will be the next dilema.Ashly Audio of Rochester makes some really sweet 31band mono's.I have an older PEQ and before I dish out $ I'll get that little bug out.

I'm positive that movies are going to be 110% better than before . :)

One last touch, and that was gasket material.I used 2mm craft foam from a fabric store. .59 a sheet, 9"x12".What a bargin! I tightened down halfway about 1mm then cranked them flush the next day.It's kinda thick so I did it in two sets.

I've gone to a metal fabricator in town and he is going to make a wire grill.I just don't have the room for a wood grill.The wire would be acoustically better.He runs a custom bike shop and thought the idea was kinda cool.It makes me a little sad to cover up this beautiful center, but I still have a seven year old with his friends, so a little added protection.

Dennis H

01-28-2006, 05:23 PM

KG, have you tried moving the center (and LR) out to the front of the sub? That cavity behind the sub and the flat top surface can't be good for the sound even with the foam you have there.

Have you tried pushing the sub back against the wall -- does it mess up the sub's response?

http://www.htguide.com/forum/attachment.php4?attachmentid=5452

kgveteran

01-28-2006, 05:46 PM

Dennis,
The subs, for the lack of a better term are flat from 10hz to 100hz at the seating position.I gave my self a double hernia moving these things around.Hence the avitar picture.I took that pic while all hopped up on pain meds.

I sit about 2 meters from the subs baffle.it's a perfect situation for an IB, but I chose a sealed system before I knew about IB.The room is only 13.5' x 15.5' x 9' .I'm quite limited.

I had the subs in each front corner and the hole in the sound was about 15db deep and about 30hz wide (42hz-72hz).Pretty bad.So I moved them around until I found the best spot.

Dennis H

01-28-2006, 06:05 PM

I'd still try setting the center on top of the sub lined up with the front edge. Just give a listen and see if it sounds better.

kgveteran

01-28-2006, 07:09 PM

I'll give it a go. I do have a sync feature on my processor if the sound isn't right.

Edit:I tested the center at the back of the sub.There was a picket fence in the lower midrange and then a bloated 120hz.

I moved it to the edge of the sub baffle.Re measuered and the picket fence was gone and the peak was at 113hz(it was about 15-20 cycles in either direction).I set up my PEQ at 113hz and wide enough to get the whole peak, and reduced it by about 6db.Boy ,did that clean up the bloat.

**** To all reading this, understand that these problems are room related.I close mic tested this center channel and it was quite flat throughout its operating range****

I thought that there would be an "in your face " sound with it just 2 meters from me and there was not.I'll leave it there and see if everything else sounds cleaned up too.

This can be looked at as a "boundry compensation" circuit :)

kgveteran

01-29-2006, 11:16 AM

Well, in the new position I watched "Robots".Chapter 6-8. What a breeze.Voices are clear with no edge.I recorded levels with peaks up to 100db (much too loud for me, but to prove a point about headroom).

For 400.00 (keep in mind I payed a cabinet maker 125.00) 275.00 sans the cabinet, you'll hard pressed to find a brand new center of this quality. I just can't get past the detail of the soundtrack.No matter what is happening on the screen the clearity is incredible

Keep in mind also that I'm only using a 100wpc B&K St-140 (only one side) I plan on running one amp for the center(biamped).

Edit: Also I measured their location and they are on the 1/3rd line of the room lenth.Would this be concidered near field monitoring ?

Curt C

02-14-2006, 02:41 PM

kg,

Glad to hear the CC's came out to your liking. Of course Kudos need to be given to Dennis Murphy for sharing his measurements. Always good when a plan comes together...

C

Curt C

02-14-2006, 02:52 PM

I'm hoping Curt C will chime in and tell me if there is a need for changing the XO design slightly to accomodate this mod in dimensions. I wanna go from 12.5" in height to 10.5-11" at most.

ssabripo,

Sorry for the late post, Don't know why, but I don't get over to this forum very much. While there will be 'some' change in diffraction due to the baffle changes, I suspect it will be quite minor. You could model it using the BDS sortware available over at the FRD Consortium, and see for yourself. -It won't be a showstopper I'm sure. feel free to email me if you have any further questions...

C