Filling a missing niche in accomplished designs

[Hdale85]

Sound good Jed.

[cjd]

So another concept I've been mulling but done nothing at all with was a WWMTMW with the lower W monopole, and the WMTMW dipole (though perhaps not the tweeter). My thought was to use a single 4ohm RS225 as the monopole woofer and kind-of .5 it.

In fact, if I had more time with Ryan's drivers I'd whip up such a baffle and toss the RS225's and RS150's in there to see if it would even work.

Ideas a million. Time, limited. :P Well, space is also limited - can't just go hog wild on projects.

C

[Jim Holtz]

(Jed) Also, If you are craving a 3-way with the W4 titanium, I believe Jim Holtz is creating a mini-Statements you should check out. I think it has dual Rs225, W4, and a ribbon tweeter.

Hi Jed,

The Mini uses (2) RS180's rather than the RS225's the Statements use. F3 should be around 40 Hz.

I'm following this thread with a lot of interest. I'm learning about di-pole designs from Jon and I totally agree with your comments about open back mids. The sound becomes very open and spacious.

Jim

[cjd]

Jim,

You only have the upper midrange open :P

Human voice core range is monopole in the Statements, as is the lower half of the Violin's range, etc...

Granted, this is the range where a lot of spacial cues exist...

C

[Jed]

updated priority list based on requests and needs. Still have to decide on finalizing driver selection. Also, I probably won't be able to get to all these designs this month. :W I'm thinking 1-4 could happen, and at least 1-3- no problem.

1) Small Fullrange- - 5
2) Small MT-- 8 (Could use TB W4 and ??? for tweeter)
3) Small MTM-- 7 (TB W4 or RS125 and ??? for tweeter)
4) Efficient design---6 (This could be combined with MMTMMW RS125 or W4, if W4 I may need a few drivers sent to me as I can't afford 8 of TB just for testing purposes. Sealed RS270 or RS225 or Usher 8137 woofer)
5) MMTMM(W) narrow side woofer ---6
6) Open Baffle-- 5 requests
7) MTMW narrow with side woofer- - 4 (this could be the same as MTM with a bass bin or #2)
8 ) Smallish 3-way with dome mid/TB -- 4
9) Paper woofer---- 1
10) Inwall--- 1
11) Ultracheap---1
12) Outdoor speaker

[cjd]

One more comment: while it is a nice driver, 99% of the time the RS150 is the way to go over the RS125. Volume requirements aren't that far apart, usable range is only very slightly more extended on the RS125 (but not enough to really open up tweeter options significantly)...

C

[Jed]

Based on the distortion measurements I've seen from Augerpro and Zaph, they are very close in performance but the edge does go to the RS150 if used below 1.5k and the RS125 is pretty clean to 2k.

[Jed]

Alrightly gentlemen, it's time to pick a tweeter for the MT and MTM tangband W4 designs, so I can start placing orders. :T

[Jim Holtz]

Jim,

You only have the upper midrange open :P

Human voice core range is monopole in the Statements, as is the lower half of the Violin's range, etc...

Granted, this is the range where a lot of spacial cues exist...

C

Hi Chris,

I'm not sure what frequencies you're defining as the mid range. The W4's are crossed 2nd order at 350 Hz. and 3750 Hz. With a 2nd order roll off they'll still be adding significant output at 200 Hz. and 5000 Hz. That should cover 95% of the mid range and part of the lower treble. Isn't that correct?

Jim

[Jed]

This could also be done as only MMTMM without the W and that way keeping cost down and efficiency higher. E.g. with 4xRS150.

Agreed- I'd be tempted to go with something like the SEAS ER18, which I have experience with in a previous design, my GMK7 design with RS52, and MHT12 tweeter. Although that is getting kinda large in an WWTWW format, unless of course we did an MTMWW with the MTM section open baffle to say 200hz.

[Jed]

Hi Chris,

I'm not sure what frequencies you're defining as the mid range. The W4's are crossed 2nd order at 350 Hz. and 3750 Hz. With a 2nd order roll off they'll still be adding significant output at 200 Hz. and 5000 Hz. That should cover 95% of the mid range and part of the lower treble. Isn't that correct?

Jim

Jim, the important thing here is to trust your ears, as you know. Your open back midrange enclosures, or shall we call them short tranmisssion lines, definitely contribute to a clean sound because there are no or very small amounts of the rear wave bouncing back through the cone. Now, this can also be done effectively in a sealed back design with appropriate damping, but its a sure thing with an open back!

[Brian Walter]

In my experience, one is better off with diopole in the 300 Hz down to 75 Hz area at the least, monopole above and below if that's all you can do.

Have done that. Optimum seems to be diopole up to at least 800-1,000 Hz. Not such a big deal above that.

~Jon

I will have to admit that I may also prefer the dipole from 75 HZ to 300 HZ region, but I thought this may add to the complexity of the design, I don't know. Maybe a Cardiod bass bin like John K uses on his NAO might also be an option.

There really aren't any reasonably priced open baffle designs around that I am aware of. Also the open baffle designs that Jon has tend to be rather large, with dual 12" woofers and such. Not everyone needs that much SPL.

I'm personally thinking of trying a Maggi with an RSS265 HF in a Cardiod setup, unless something else more appealing comes along.

Brian Walter

[Johnloudb]

Loses all the diople benefits of pitch definition and consistent power response of fundamentals and harmonics, in the frequency range where it's the biggest problem.

In my experience, one is better off with diopole in the 300 Hz down to 75 Hz area at the least, monopole above and below if that's all you can do.

Have done that. Optimum seems to be diopole up to at least 800-1,000 Hz. Not such a big deal above that.

??? You're saying midbass should be dipole also? Dipole 75Hz - 1000Hz+ if possible. OK.

I was thinking dipole 5-6 in. mid-woofers, dipole tweeter (B-G neo3), can always buy a sub. Maybe not for this project.

[Jim Holtz]

Jim, the important thing here is to trust your ears, as you know. Your open back midrange enclosures, or shall we call them short transmission lines, definitely contribute to a clean sound because there are no or very small amounts of the rear wave bouncing back through the cone. Now, this can also be done effectively in a sealed back design with appropriate damping, but its a sure thing with an open back!

Hi Jed,

I fully agree that it all comes down to what we hear. However, there is a significant amount of sound coming out of the back of the speakers. I didn't realize just how much energy went backward and is then bounced forward into the back of the cone in a box design. I'm not sure if it's possible to attenuate that much energy regardless of how much stuffing you put into the speaker.

To clarify, I didn't take Chris's comments wrong at all and I'm not being defensive about the Statements. Heck, every speaker is a large combination of compromises.

I'm just trying to pin him down because he's said that before. I don't know that my perspective is the correct one so it was a request for more knowledge rather than a confrontational question if it came across that way. It was unintended if it did.

So, now that we've got that out of the way, is 200 - 5K Hz. 95+% of the mid range or not?

Jim

[Jed]

Jim, to answer your question I'd say no for your design because the woofers are covering a substantial amount of midrange as well.

Image not available

[Johnloudb]

ribbon tweeter

Jim, the important thing here is to trust your ears, as you know. Your open back midrange enclosures, or shall we call them short tranmisssion lines, definitely contribute to a clean sound because there are no or very small amounts of the rear wave bouncing back through the cone. Now, this can also be done effectively in a sealed back design with appropriate damping, but its a sure thing with an open back!

Yes, but open backs also add ambience creating a larger soundstage.

I do like W4's for this project. Hope you do an MTM after full-range W4 though.

1 vote for ribbon tweeter.

[Jim Holtz]

Hi Jed,

Thanks for posting the chart. I do have that one along with others. Here is the description from the audioDIYcentral.com that came from Stereophile a few years ago.

(paste)

What is bass, mid, high?
This is subjective. See the music range chart for a graphic representation.

low bass: 20 Hz - 40 Hz
---mid bass: 40 Hz - 80 Hz
------upper bass: 80 Hz - 160 Hz

low midrange: 160 Hz - 320 Hz
---midrange: 160 Hz - 1,300 Hz
------upper midrange: 650 Hz - 1,300 Hz

Treble: 1,300 Hz - 20,000 Hz
lower treble: 1,300 Hz - 2,600 Hz
---mid treble: 2,600 Hz - 5,000 Hz
------upper mid treble: 5,000 Hz - 10,000 Hz
----------high treble: 10,000 Hz - 20,000 Hz

(End of paste)

BTW, I'm enjoying the responses to your question. It's obvious that there is no one speaker that fits everyones needs.

Jim

[Jed]

I do like W4's for this project. Hope you do an MTM after full-range W4 though.

1 vote for ribbon tweeter.

John,

The plan is to do 3 designs using the same driver. In this case it will be the W4 by popular demand.

The sequence for ease of R&D will be W4 fullrange, W4 MT, W4 MTM. There will be baffle step and non baffle step crossover so people can mount these on the wall out in the room if they like. I'll use a slot port to save space and allow the bass to fire forward so wallmounting or placement near a wall won't be an issue.

Then, after that is complete and a tweeter selection is finalized, I'll tackle the MMTMM or MMTMMW design that everyone seems to want, either transmission line/open back mid or not.

[Landroval]

Jed, the frequency ranges of the instruments are just the "primary harmonics" (no idea of the correct term). If I'm not totally wrong, resonances go much higher. Have you tried listening to a violin cut to 2000Hz?

[Jed]

Jed, the frequency ranges of the instruments are just the "primary harmonics" (no idea of the correct term). If I'm not totally wrong, resonances go much higher. Have you tried listening to a violin cut to 2000Hz?

I don't disagree with you about harmonics etc. The chart was to illustrate that voice, commonly associated with the midrange, would be definitely handled by the RS225, or at least significantly so in the Statements design where it is crossed over to the open back mids. This is not a fault of any kind of the design, just an observation I wanted to point out to Jim.

[Jed]

Back on topic.

Guys here are some potentials for tweeters in the MTM and MT.

Image not available

Foutek Ribbon CD1- this looks interesting and would work well LR4 at around 3.5-4k. $58
2 votes

Image not available

22TAF/G (H1283) Alum/Magn. Alloy 22mm dome $27.45 Would work well in either MT or MTM


Image not available


D26NC55 1" Textile dome tweeter $28.90-- proven tweeter and would work well in either design.
1 vote


Image not available


Aurasound NT1-204-8D 3/4" Titanium Dome Tweeter $8.75

[Hdale85]

ok I see you updated your post let me look at those.

[Jed]

Which ribbon is that and whats it cost? We already know the D26 goes well with the W4's so maybe we should try and pick something different :B Unless its the best option. While I would love to have a ribbon tweet in this design it may add quite a bit to the price tag...depending.

the Fountek CD1 is only $58. Pretty affordable for a ribbon.

[Hdale85]

Yeah I edited my post a couple times...first because the D26 has not been paired with the W4's I was confusing 2 different designs...and then because you added the info about the tweeters So for the ribbon we're looking at....roughly 300 in drivers for the MTM? Thats really not that bad especially if the crossover is kept simple enough to keep the parts count down and cost down.

[Jed]

Yeah I edited my post a couple times...first because the D26 has not been paired with the W4's I was confusing 2 different designs...and then because you added the info about the tweeters So for the ribbon we're looking at....roughly 300 in drivers for the MTM? Thats really not that bad especially if the crossover is kept simple enough to keep the parts count down and cost down.

I'm typing in info as fast as I can to keep up with this thread. :T

[Hdale85]

What kind of sensitivity do you think the final MTM or MT would have with the ribbon? The W4's are 87db and the Fountek 89db.

[Jed]

What kind of sensitivity do you think the final MTM or MT would have with the ribbon? The W4's are 87db and the Fountek 89db.

Well, good questions because people are looking for easy loads on amplifiers, which might suggest I do a series woofer connection on the MTM which would result in a sensitivity around 84db with BSC or 87db without. For a lower impedance version (parallel configuration on the woofers) we are looking at 88-89DB with BSC.

[Hdale85]

Well I for one don't mind the lower impedance so would take the higher sensitivity. I'll be powering these with a chipamp. Cheap and 4ohm stable

[Hdale85]

Ok well my vote is like this. I vote 1 for the Fountek because ribbons are awesome! And secondary I vote for the D26 because of small form factor and high sensitivity.

[Jed]

The vifa and a tweeter like the seas make the most sense for an MTM. Better integration and less lobing issues because I'll cross over lower with these tweeters.

[Dean100]

Been gone a couple of days, but will throw in my "vote" anyway.

Would love to see an Open Baffle design. Sort of an "introduction" to Open Baffles that is not expensive (say $300-$500 Max) I really want to hear what "boxless" speakers sound like.

Or is there already something along this line already out there?

[Johnloudb]

Foutek Ribbon CD1

Well I for one don't mind the lower impedance so would take the higher sensitivity. I'll be powering these with a chipamp. Cheap and 4ohm stable

I agree, most amps can handle a 4 ohm load of high sensitivity (89+ is good). When you get to the MTM design.

Foutek Ribbon CD1 ... like very much.

[cjd]

In response to Jim (and I started this back when the chart was the last post in the thread...)

I'd really want to see -6dB no lower than 80Hz to say 95% of midrange and I'd prefer -3dB I think. That still misses out on the low of the low human vocal range.

IMHO there is very very good reason when I look at instrument families and what produces sound where, that THX chose 80Hz to cross to a sub. Whether they relied on that or not I can't say.

I guess what I need to do is pick up the same drivers you've got in the Statements and add that .5 monopole woofer and instead go all open baffle with the WMTMW. Then bring that to some DIY event where you can compare. Would certainly be interesting. Who knows what results we might arrive at.

[Jed]

Been gone a couple of days, but will throw in my "vote" anyway.

Would love to see an Open Baffle design. Sort of an "introduction" to Open Baffles that is not expensive (say $300-$500 Max) I really want to hear what "boxless" speakers sound like.

Or is there already something along this line already out there?

Mark K is working on an inexpensive OB, it'll have active EQ though- which in most cases is necessary because of the inherent 6db per octave losses in the bass. Which is why we have been discussing an open baffle mid down to 200 hz or so to monopole bass. JonMarsh and others have commented this is not optimal- scientifically speaking. However, sometimes it sounds good as such designs have been created already with excellent sonics. Largely, monopole bass is very room dependent.

[Landroval]

Fountek Ribbon CD1- this looks interesting and would work well LR4 at around 3.5-4k. $58

What kind of sensitivity do you think the final MTM or MT would have with the ribbon? The W4's are 87db and the Fountek 89db.

MT with NeoCD1 @4-5k is probably going to be great, but MTM is in my opinion a no go. You can't crossover much lower than that because of the distortion of the tweeter and an MTM with that high xo-frequency is doomed with lobing and interference problems.

---

Edit: And to the OB-mid question I'd like to say I like the idea. There's many DIY and retail speakers following that format and they definitely work nicely. No backwave disturbing the mid and also dipole radiation pattern (less interaction with sidewalls etc.)

Here's some examples:

Nola (all models):

http://www.nolaspeakers.com/

ProAc Future's:

http://stereophile.com/floorloudspeakers/1000proac/

http://www.acdc.com.tw/speaker/proac/future_family.jpg

Tony Gee's Modulus and Progress:

http://www.humblehomemadehifi.com/Modulus.html

http://www.humblehomemadehifi.com/Diary.html

Troels Gravesen's Acapellas:

http://www.troelsgravesen.dk/download.htm

http://www.troelsgravesen.dk/Point75i.htm

http://www.troelsgravesen.dk/AcapellaSEas.htm

[Scottg]

..upon looking at the eff. and impedance of the Tangband vs. the little Fountek.. looks good. :T

Basically the resistance required to drop the output of the tweeter near a crossover of 3 kHz to match a single Tangband should work out well for a mostly resistive load (including zobels).

The only potential "fly in the ointment" is its horizontal dispersion.. which is basically the same as a their other tweeters and as the G2si. 45 degrees off-axis will result in about -4db (vs on-axis) at 7 kHz. At 5 kHz it will be about a -2db loss in sp. This could lead to image placement alterations and only modest tonal changes for multiple listeners. Still, it looks pretty good for the application. Note however that it will not sound as good as a non-laminated true ribbon (i.e. G2si), but its less expensive and is far more robust (and likely has better non-linear distortion).

[Johnloudb]

MT with NeoCD1 @4-5k is probably going to be great, but MTM is in my opinion a no go. You can't crossover much lower than that because of the distortion of the tweeter and an MTM with that high xo-frequency is doomed with lobing and interference problems.

Thanks, I get it now.

Yes, the MT with NeoCD1 sound like a winner.

[Jim Holtz]

In response to Jim (and I started this back when the chart was the last post in the thread...)

ll open baffle with the WMTMW. Then bring that to some DIY event where you can compare. Would certainly be interesting. Who knows what results we might arrive at.

Hi Chris,

In an effort to quit hijacking Jed's thread, I decided to respond in the statements thread here: https://www.htguide.com/forum/showpo...&postcount=365

Sorry we got off on a different subject Jed. ops:

Jim

[Ray Collins]

How about an Aurum Cantus rbbon?

Ray

[Jim Holtz]

Hi Scott,

I do have to take some issue with this remark and agree with the more robust portion.

Note however that it will not sound as good as a non-laminated true ribbon (i.e. G2si), but its less expensive and is far more robust (and likely has better non-linear distortion).

The difference between the NeoCD3.0 and JP3.0 is an element weight of 18 mg. Vs. 11 mg. I've listened to speakers with LCY, Aurum Cantus G2si, G2, G3 and Fountek JP2's and Neocd3.0. I've also compared the JP2's and NeoCD3.0 back to back. I can't hear any difference other than what could be contributed to different crossovers in any of the ribbons. All are fine ribbons. Just an FYI: the Neo line and JP line of Fountek ribbons have interchangeable elements with no crossover changes required.

Now, back to Jed's regularly scheduled thread. I vote for the new little Fountek Neo1.0's. They are an excellent match if the distortion profile is under control. If they distort too much, the next vote would be for the Aura NT-1's. That is a true bargain tweeter. :T

Jim

[Scottg]

Hi Scott,

I do have to take some issue with this remark..

Jim

Let me guess - very low output impedance for the amplification? Still, such amplification is more than likely to be used by most people - especially for an HT application. So, even if there is a difference with some amplifiers, my comment is likely moot.

(I guess what I'm saying is - some amplifiers can rather immediately expose the difference between ribbons, reinforced ribbons, planars, etc..)

[Jed]

I think a lot of people are looking for something a bit different. The Fountek CD1 looks like a good value IMHO, and I can measure its distortion when I get some. That's not a problem. I don't think it will work well in an MTM as I noted above as there will be vertical lobing issues if crossing at 4K in an MTM. Might not be noticeable for some folks depending on where you are sitting, but considering I plan on making the MTM a center channel option as well, I think the little Vifa is the answer for the MTM. It'll be versatile for a wide variety of applications. Plus, at 89db sensitivity, I'm a bit worried about the CD1 keeping up with the W4 titaniums in a parallel configuration MTM, with no BSC. It won't really be more work to have different tweeters in the MT versus the MTM, but as long as the MTM folks are happy with the Vifa, lets proceed. I could do an MTM and MT with Fountek CD3 as I could cross lower with those ribbons.

So, as it looks right now people want:

W4 fullrange,

W4 and Fountek CD1 MT

W4 and Vifa D26 MTM

MMTMM(W) To-be-determined

[Hdale85]

CD3 is much more expensive. I think the D26 is perfectly fine for the MTM and the small form factor will keep the size of the enclosure down some if needed. I would love it as a center option anyways :B

[dlneubec]

I know you have all decided on the TB driver, but let me point out that one benefits of the RS line of drivers are that they come in 4ohm and 8ohm versions, giving them much greater flexibility when planning multiple designs with different woofer/midwoofer mixes, that is where overall impedance is an important issue. My HOSS project with the RS150-4's and RS28 has come in at over 6ohms with two RS150's in series.

FWIW, I'd vote for the RS drivers for the flexibility reason and the fact that they are half the price.

I'd also vote for the D26NC55 as the basic tweeter due to it's flexibility at lower crossover points, acknowleged low distortion and flexibility in CTC spacing.

[sprint_9]

I know you have all decided on the TB driver, but let me point out that one benefits of the RS line of drivers are that they come in 4ohm and 8ohm versions, giving them much greater flexibility when planning multiple designs with different woofer/midwoofer mixes, that is where overall impedance is an important issue. My HOSS project with the RS150-4's and RS28 has come in at over 6ohms with two RS150's in series.

I also agree with this, plus the RS drivers cost less.