Help choosing a design for some towers

[bf_brock]

So I'm looking to build a pair of full-range towers for HT and Music use. They would be used mostly for HT use but their music performance is very important. I want a dynamic speaker with good low end bass performance. Oh, and good off-axis performance is required.

I currently have JBL S38II's and want something that will perform substantially better. They aren't bad speakers especially considering what I paid for them, but there's only so much a fairly low cost consumer bookshelf speaker can do. The size of the towers isn't a concern, I can handle large towers but they need to be able to be placed close to the back wall.

So now to design suggestions. I'm not experienced in making anything but pretty basic subwoofers so I'll need to use an existing design or work with one of the gracious experienced designers around here to make something new. As for my woodworking skills, well I do know people who can assist me in that department.

Looking around at some of the previous designs I've had interest in Jon's M8a designs (like the M8ta and Tibor's MTM's), the Statements and I like the idea of Zaph's Waveguide but maybe with the Dayton RS225's in a larger tower instead. The Statements I think have to be ruled out because they require placement away from the wall. Budget wise I probably have to stick to ~$700 maximum for the parts. Of course the less I have to spend the better but I do want something that will last and won't leave me wanting to upgrade right away. I have no idea how much the cost is for the M8ta's and an MTM version. Also, could the M8ta's be modified to be a TMM for increased bass performance?

Sorry for the long winded post but I figure it's best to get as much info out at the beginning.

[---k---]

For $700 you can build the Khanspires. If not that, maybe the Dayton RS TMWW.

Modifying existing designs is not for a newbie, and designers are reluctant unless you strike their fancy with something cool. It can take a lot of work.

[PoorSound]

http://customanalogue.com/elsinore/elsinore_index.htm

there you go.

I've built these, I'm actually the second comment on the website. They are outstanding. I'm building a center channel using the same crossover, minus the woofer section.

do it!

[cjd]

http://customanalogue.com/elsinore/elsinore_index.htm

there you go.

I've built these, I'm actually the second comment on the website. They are outstanding. I'm building a center channel using the same crossover, minus the woofer section.

do it!

Mmmm, i love it when physics is... kinda tossed out the window.

Interesting looking design.

[PoorSound]

Mmmm, i love it when physics is... kinda tossed out the window.

Interesting looking design.

I'm not very fluent in speaker designs...I'm starting to learn as I go along as these were my second time building a set of speakers. I'm not quite ready to do my own design from scratch, but what do you mean when you say physics are tossed out the window?

[cjd]

Vertical positioning of the head will be critical given driver spacing - I assume that's a MTM up top. The ability to place those drivers in close proximity is there with the truncated frames, yet it goes beyond not coming close but puts them quite far apart. Yet the woofers are packed in closer. Center to center spacing. It will comb on the vertical plane (and horizontal if you place it "on its side" - pretty badly in fact - very easy for that to result in hard to understand dialogue, fixed by moving your head to one side an inch or two... but 3 inches too far.

It's not uncommon, especially on systems with "wideband" drivers and "supertweeters"

C

[bf_brock]

Thanks for the responses guys.

How would you compare the sound and performance of the Khanspires to CJD's Dayton 3-ways? -k-, In your post on the Khanspires you mentioned that they were a step down from CJD's RS 3-ways. Is this just in the bass performance? Do the RS 3-ways require placement away from the wall or are they just a deeper cabinet design that would would make them stick out further into the room? Could the Khanspires be optimized for lower extension, like do an optimized ported version?

Also on the Khanspires can the tweeter be easily substituted for the Seas 27TDFC/TBFC? From everything I read the Dayton tweeter is rolled off on the top end more than the Seas and a little laid back. The Seas is a little more "open and airy". That's what I read, I haven't actually heard either of them. I just know that I don't like a laid back speaker (nor way treble forward either for that matter) and it sounds like the Seas would be more to my liking.

[---k---]

The Khans and CJD's Dayton 3-ways will sound very similar. That was one of the goals. The reason it is a step down, is that it uses 2 - 6" mids and 2-8" woofers as opposed to 2-7"mids and 2-10" woofers. It also uses a somewhat less complex crossover.

The Khan's won't have as deep of bass extension as the Dayton 3-ways. Both designs are sealed, but can be built ported. The Khan's would need about ~2" more of depth to do ported. It would be then similar in bass to the Statements. The Dayton 3-ways don't really need to be ported.

Khans are designed to be 1' - 2' off the wall. Not sure on room positioning with the RS 3-ways. But, if you look at the photos of CJD's room, you see that he has the close to walls, but in an open door way.

You can't just swap the tweeter, you need a different crossover. But, CJD is a real nice guy and has said that he would do a SEAS crossover for people. When he was taking measurements, he stuck a SEAS tweeter in and got those measurements too. Not sure which SEAS tweeter, but.... I'm not versed well enough to talk about the differences. Someone had a real good post on the PE board recently describing the differences - it is too bad the PE board throws away old posts and isn't searchable.

The Khan's will fit your $700 budget. CJD's Dayton RS 3-ways will bust it. I was suggesting the Dennis Murphy TMWW, which can be built for ~$500.

http://htguide.com/forum/showthread.php4?t=15323

[bf_brock]

Ah, I see. There are a lot of speakers around here that are using the Dayton RS's. Looking at the link to Dennis's TMWW I would assume it would sound similar to yours, but with less midrange energy. I can't say for sure but I think I might like having two drivers in the midrange like the Khan's. But, I also like saving a couple hundred dollars...

[---k---]

Yep, trade offs.

The DM TMWW should sound similar. They use the same drivers and target a flat response. There will obviously be some differences. I agree with you that the mids are where most of the music is, so two mids is better than 1. Bigger, more expensive typically is better. How much of a difference, I can't say. A few here have now heard both, and maybe they can comment.

[bf_brock]

If someone has heard both I would love to hear what they have to say.

So the Khan's would probably only need another 2" depth for a ported design? That's definitely doable.

[cjd]

The Khans won't have more midrange energy, but they're going to have less distortion there (both from use of a steeper slope in the crossover - breakup nodes in the RS150 are more attenuated - and due to splitting the load over two drivers, so less excursion to hit the same SPL)

The RS28 is not laid back, just very analytical. "Airy" usually comes with distortion of the even order type. I used an older model 27TDFC. I have to do a compare now with the new models. I'm wondering if the new TDFC's aren't up to snuff... more on that as I get data.

C

[Jim Holtz]

If someone has heard both I would love to hear what they have to say.

So the Khan's would probably only need another 2" depth for a ported design? That's definitely doable.

I have heard both. I built the RS 3-ways and heard Ryan's Kahanspires at the Iowa DIY event last fall. I found the two speakers to be almost identical in sound except for the top end because I used the Seas 27TBFC/G tweeter and prefer it to the RS28. Personal preference only, however.

Both are excellent speakers that perform way, way beyond the cost to build. Dennis Murphy made some very flattering remarks about the Khanspires so you know they sound good. :T

Pick your visual effect. You can't go wrong with either speaker, IMHO.

HTH

Jim

[bf_brock]

cjd - Thanks for the info. I do listen at varying volume, sometimes very loud so having the extra excursion available may be beneficial. Although my current JBL's only have a single midrange and woofer and their ability to play loud (and not sound like cr@p when doing so) is actually one of their best features. I am curious on any data/comments you come up with regarding the tweeters.

[bf_brock]

Jim - Thanks for the comments on both designs. I like to hear that they perform well beyond their cost to build. That's what I'm looking for! How would you describe the difference between the two tweeters, in your opinion?

[cjd]

TBFC is brigther (it has a high resonance peak at ~24kHz IIRC)
TDFC is airier (it's silk and has a mild rising response at the top)
RS28 is analytically clean, probably due to a lower response peak at a higher frequency, and that 3-5dB dip above 15kHz (it's actually back up to nominal output level at 20kHz).

The TBFC hits me in an odd spot and I can't sit it as long. They're all fine tweeters.

[---k---]

Analytical has such a nasty word association to it. I don't think you're intending to be negative on it. People should understand that.

[---k---]

Ahh, here is what I was thinking of, by Roman Bednarek

http://www.pesupport.com/cgi-bin/config.pl?read=398663

This is just my opinion so others may disagree. The RS tweeter is very smooth, clean and accurate. It doesn't have much shimmer or sparkle at the top end. Percussive instruments that excite frequencies in the mid-treble such as ride cymbals, triangles and tambourines sound very good while higher frequency tones like those from a high-hat cymbal sound more laid back.

The 27TDFC is a very good tweeter as well and is the one that I prefer because it just seems to have more "life" to it. The top end has much more shimmer and sparkle and seems to provide a bit more depth to the presentation. It is the opposite in the fact that high-hat cymbals sound great and ride cymbals/triangles/tambourines aren't quite as clear sounding due to less of an emphasis on the fundamental tones and more of an emphasis on higher harmonics.

So the main difference is in the top end where the 27TDFC has a lot more life. I find the RS tweeter to be smoother in general. Of course a lot depends on the crossover but some of the fundamental differences cannot be compensated for.

Others, like Jeff B say:

http://www.pesupport.com/cgi-bin/config.pl?read=392746

Interesting that you mention the RS28a. I moved from working with the 27TDFC on the Dreydels to working with the RS28a on my current design. It is a very good tweeter; very linear, with very low distorion, and a very low Fs. The only problem it has is the dip in response at around 17-18khz. Although is rises above 20kHz, we can't really hear that. What we do hear is a little loss of air due to the roll-off that begins around 12kHz and falls off 5 dB by 18kHz. This is not hard to compensate for though. Since I have to pad it down some already I can use some of that to contour the response and introduce a rise in my tweeter circuits's transfer function that adds back in about 3.5 dB by 20kHz. When this is done the slightly dark quality is removed from the tweeter and it really sounds nice.

Everyone has an opinion. The design also makes a difference as pointed out.

[bf_brock]

Perfect. While I realize that the descriptions are just peoples opinions I think it paints a pretty good picture of how they sound. Especially since most people seem to have a fairly similar view. I think that gives me a fairly good idea of what to expect. Thanks.

Now I just have to read over the construction threads again and make my decision. If I do the Khan's I'll want to do a ported version I'll have to workout the details. If I do a ported version does the crossover need any changes?

[cjd]

Ported, you'll just need to upsize the box and pick your tuning frequency.

The other way to go is to mount it on top of a 15" subwoofer with the box "shortened" so the tweeter height remains the same. Keep it sealed, and just make the box deeper to maintain volume.

I've a request in for a WWMTMWW version... may mess around with that too, somewhere along the way.

[Jim Holtz]

Jim - Thanks for the comments on both designs. I like to hear that they perform well beyond their cost to build. That's what I'm looking for! How would you describe the difference between the two tweeters, in your opinion?

Hi,

Chris made a lot of good comments that I generally agree with. However, I would add a couple thoughts.

The Seas 27TDFC is the "lightest" sounding tweeter of the group and has the top end air that allows you to hear the atmospheric sounds often associated with a recording in a church or hall.

The RS28 has more body and is extremely clean sounding but sound a bit dead to my ears in the top octave unless the frequency response is shaped to eliminate the 5 db dip. Other than that, I think it's a nice tweeter.

The Seas 27TBFC/G has the full bodied clean sound of the RS28 but has a sparkle in the top octave that I find particularly appealing. Chris says the 26K peak bothers him but it's beyond my hearing capability so we differ in our favorites.

The 27TBFC/G if my favorite budget 1" dome tweeter. I thinks it's unbeatable under $100. BTW, it's lots cheaper than the RS28 too. :T

My $.02 worth...

Jim

[bf_brock]

Actually I was just looking at the Kahn's construction and it looks like the tweeter center height is 34". I was actually thinking I may want to change the height to bring it closer to my ear level when seated which is about 40". Not sure if I want to add a sub to the cabinet, although I have contemplated it. lol I do listen to rock music mostly and like hard hitting bass.

I like the sound of sealed enclosures but when I listen to music I strictly listen in two-channel mode or pure analog, especially with vinyl. I'm not sure that the sealed version would have enough SPL in the lower frequencies. I could be wrong though. One thing I do want if I go ported is that I want a low Q tuning.

[Jim Holtz]

Actually I was just looking at the Kahn's construction and it looks like the tweeter center height is 34". I was actually thinking I may want to change the height to bring it closer to my ear level when seated which is about 40". Not sure if I want to add a sub to the cabinet, although I have contemplated it. lol I do listen to rock music mostly and like hard hitting bass.

I like the sound of sealed enclosures but when I listen to music I strictly listen in two-channel mode or pure analog, especially with vinyl. I'm not sure that the sealed version would have enough SPL in the lower frequencies. I could be wrong though. One thing I do want if I go ported is that I want a low Q tuning.

Check out the cabinet drawings and box tuning for the Statements. There is one for sealed and one for ported. Obviously, you'd need to adjust driver spacing and internal mid compartments for the Khanspires but you'd have a cut list of the main panels. The ported bass in the Statements is exceptional, IMHO. If you go sealed with subs, it is just a hair tighter in the mid bass but by very, very little. Curt did a killer job tuning the cabinet, IMHO.

BTW, I set the tweeter height at 38" but there's room to slide the drivers higher on the cabinet for a 40" tweeter height.

HTH

Jim

[bf_brock]

Let me put it this way. I don't like the laid back, kind of rolled off top-end I've heard on say Energy Loudspeakers but I can't stand the overly bright top end of say Monitor Audio speakers. If any of the tweeters fall somewhere in the middle I think it would work for me.

As far as music goes I mainly listen to rock; anything from say The Mars Volta, Tool or Chevelle to Led Zep, Dire Straits, the Stones, Eagles, etc. I also like female vocals and do occasionally listen to classical music (I love the cello). So...Pick the tweeter that fits best.

[Jim Holtz]

Let me put it this way. I don't like the laid back, kind of rolled off top-end I've heard on say Energy Loudspeakers but I can't stand the overly bright top end of say Monitor Audio speakers. If any of the tweeters fall somewhere in the middle I think it would work for me.

As far as music goes I mainly listen to rock; anything from say The Mars Volta, Tool or Chevelle to Led Zep, Dire Straits, the Stones, Eagles, etc. I also like female vocals and do occasionally listen to classical music (I love the cello). So...Pick the tweeter that fits best.

I think the Seas 27TDFC would fit your music and tastes best based on your comments. Be prepared to start hearing a lot "more" in your recordings. The RS and Seas drivers are quite accurate and won't mask the grunge of poor recordings. A lot of rock is recorded for car radio and little time is spent creating good recordings to be enjoyed on good systems.

Jim

[bf_brock]

I think 38" would be a good compromise for my listening height and other people who would be forced to experience my speakers. lol Right now my speakers are on stands that are too short so technically no one is at the right listening height so anything closer to the appropriate height is bound to sound better.

[---k---]

Yeah, it is at 34", but I always expected to raise it another 1" - 2" with speaker feet. Just adjust the depth and area below the woofer to taste. And do checkout the Statement drawings. I used them during construction myself.

The Khans are fairly strong in room down to ~35hz - 40hz. CJD and I played with turning the switching from Large to Small w/ a sub and a 50hz crossover. There wasn't huge differences. For 2 channel music you may not really notice the lack of that last bit unless you're listening to pipe organ music. But, either way. Whether you do sealed or ported, it isn't a big deal. I have a refrigerator sized sub that I must justify.

btw, what is your location? If Chicagoland, you're always welcome to stop by for a listen.

[bf_brock]

I do realize that a lot of rock isn't mixed or recorded very well. I already get to experience that with my current system and can imagine that better components will bring more of that out. I'm ok with that. Bring on all the horrible detail.

One thing that I have found is that a lot of the bands I listen to seem to put more effort into their vinyl releases and they tend to be mixed better.

Thanks for the tweeter suggestion by the way. Sounds like the one I may be leaning towards using.

[bf_brock]

I'm located in Sacramento unfortunately. I guess if I want to hear them, I've got to build them.

The speaker feet idea. Duh! I had always planned on a down firing port if I was going ported so lifting the speaker off the ground a couple inches with feet would automatically bring it closer to the correct height.

[bf_brock]

I've searched a lot for what the performance differences are for MTM designs versus traditional tweeter on top designs, like a TMM or TMW design. It seems that what I find is either cryptic, I don't understand what they are talking about or it's just people saying that one design sucks and the other is great. Can some break it down in more general terms about what the performance differences between the design types when properly implemented?

What kind of wire do you recommend running for the internal connections?

[cjd]

If we're talking classic two-way TM vs MTM it's largely the lobing patterns that change. A TM will have a "tilt" where the MTM will not (off-axis in the vertical plane is different above vs below for the TM). This can be useful (in my HT I put the mid above the tweeter, and the tweeter itself is above ear level - the "tilt" is in this case downward which is useful in this situation.)

Anyone that tells you one is great but the other sucks is just a bigot, probably not worth listening to their opinion.

You also, of course, have twice the surface area in the midrange on an MTM - this can balance things somewhat I think as it's not always just about moving air. Big drivers sound different than little drivers playing any given frequency, somehow. Or, more drivers. Less strain perhaps, not really sure. Could just be one of those psycho-acoustic things.

A TMM is almost sure to have center to center issues from tweeter to bottom mid (unless it's a 2.5 way) - it retains the lobing behavior of the TM while adding surface area.

Going 3-way always changes the equation so it's hard to compare. But I prefer them. Excursion induced midrange distortion in a 2-way isn't something I would have guessed I could hear, but I think I do. Subtle, mostly loss of detail - room cues and stuff, so much of it -20dB or -30dB if not lower. Things I don't really hear but am aware of (that I can only attribute to the years of violin)

Wire, use quality copper. If you want to get fancy ApexJr has great prices on super high quality silver coated copper with a teflon insulation. Make you feel all warm and fuzzy. It's actually really nice to work with, and I like it for that reason alone (insulation strips easily and cleanly, wire is flexible but stiff enough to hold some shape... solder just loves it, and insulation doesn't melt and make me retch when soldering...)

I also have spools of 12ga and 14ga from Parts Express (house brand).

C

[bf_brock]

cjd - Thanks for the information. I think that makes since. I'm leaning towards building the Khan's. The 27TDFC sounds good for the reported slightly more lively top end. Do you personally think the RS28 is a better option do to the lower frequency detail and that if needed I should just equalize the top end drop off?

[cjd]

My biggest gripe about the Seas: plastic flange. The RS28 is a rock solid aluminum flange, and has a nice looking grill to boot. Sometimes, that counts.

I quite like the RS28A in my 3-ways. I just used the Seas for the rising top end behind my AT screen (which lowers top end output).

Honestly, I'm torn as to which I prefer.

C

[tpremo55]

When choosing between MT, MTM, or TMM(2.5) I have found a LOT of variation in the sound. Some MTM designs just dont settle with me. I have a 2.5-way design that I find very enjoyable to listen to for long periods. I've also built a WMTMW (the Statements) that I like a LOT - and they don't challenge me like other MTMs have. Many well designed MT speakers have really captured my attention too (Dave Ellis' designs, the Modula MT, Scott's RS125/BM3.0 ribbon 2-way to name a few). I recommend that you take every opportunity to listen before you decide.

C, I'll add to your review of the RS28a and TDFC the cost factor. I have listened to A/B between the two and find the TDFC a little nicer, but it is also $10-$15 cheaper. Also, I think it is the TBFC (not the TDFC) that has the significany raise on the top end (correct me if I'm wrong). In the end, you cannot really go wrong with either in my opinion.

Todd

[bf_brock]

cjd - I agree, sometimes looks do matter.

Todd - Thanks for your input. I think I'm close to choosing the Khan's. I've got to go over the design details some more and make my final decision on the tweeter.

[bf_brock]

Were the Khan's bi-amped?

[cjd]

Todd: the TDFC has a rise in the top. The TBFC actually has a mild droop with a strong resonance peak at ~24000.

Cost, sure. That accounts for the nicer grill and the nicer frame. If I could get the Seas with those options for $15 I'd be all over that. Worth it IMO. Somehow.

Khans were not bi-amped. You can go that route to be sure.

C

[bf_brock]

So I've decided to go with the Khan's in a ported design tuned similar to the Statement's.

cjd - Can something be done in the crossover to lessen the dip in the RS28's response over 15k?

[Jed]

How many people can really hear past 15k? I'm good to about 17k last I checked and that was pushing it. I know because of all the distortion testing I've been doing lately. :B

[bf_brock]

True...I have no idea how high of frequency I can hear. Really I was just thinking that some people say if you can bring that dip in the frequencies up it help make the tweeter more lively while maintaining the detail the RS28 has in the lower frequency range. I think it was on Zaph's site that he said over 10K we aren't really sensitive to dips in the frequency. Since I haven't done my own testing it's hard to say what I hear. I wish my budget allowed me to get both the RS28 and the 27TDFC and find out what I like best.

[---k---]

What does the room look like that you're going to be putting these in? Get rid of the carpet and window coverings, and you won't have a problems.

Glad to hear that you're going to be building these. I really think you'll enjoy them. I wouldn't worry about the tweeter differences. Keep us up to date on your progress.

[bf_brock]

Hardwood floor, plantation shutters, 10 foot ceilings, lots of A/V equipment. Not a spot of carpet in the entire house and all the window have shutters. Does that make it fit for high frequencies?

[cjd]

Yeah, we can add a circuit to try to bring the top end up. I'll take a peek.

[bf_brock]

Thanks CJD! I'm sending you a PM regarding the parts info.

[bf_brock]

So, I'm hoping to get these started within the next couple of weeks. In the meantime I'll be finalizing the layout/design and making sure that I understand everything so as to limit any mistakes. Since I'm going ported I'll basically be following the Statements design and making the necessary adjustments needed for the Khan's.

Regarding the Khan's design drawing I want to make sure I'm seeing this correctly. Are the mids and tweeter within the same enclosure sealed off from the rest of the cabinet? Looking at the drawing it looks like the mid/tweeter portion is 6"x16.2" internal dimensions sealed from the rest of the cabinet.