Contemplating my next speaker design, what do you think?

[dlneubec]

Because of severely reduced funds these days, I'm contepmplating a project using drivers I already have on the shelf, but also drivers that are still available. I have a quad of RS180-8’s from my Mentor omni project that I can reuse. They are beat up a bit, but still usable.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=295-364

I picked up a pair of Morel MDM55 mid domes when they were on the DOTD a while back and think they would work quite well here.

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=287-020

I also have a pair of Seas 22TAFCG tweeters from one of my first projects that can be recycled. This is an extremely clean small metal dome tweeter that should be great above 3khz.

http://www.madisound.com/catalog/product_info.php?products_id=1601

An alternative to the 22TAFG are a pair of RS28AS-4’s from my Mentor omni project that are gathering dust. Driver costs by today’s prices is a little over $400 for the pair and with crossovers should come in under $600/pair.

Paul Kittinger is working out a tapered TL for the RS180-8’s in a 56 liter (gross) cabinet with an F3 of around 37hz. The baffle is sloped at 10º to get in the ballpark of time alignment to a listening position of about 12’. The speaker is 9.5” wide and only about 41” tall, so it is rather diminutive for a floor standing 3-way. The main woofer box is deeper, about 20”, to get the additional volume. The MT baffle has 1.5” chamfers that taper out by the time it joins the main woofer box. Attached is a rendered concept of the speaker.

Just looking at the manufacturers data (no measurements taken at this time) I’m anticipating crossovers points in the 800-900hz and 3000-3500hz range. I would like to use lower order slopes were possible. Sensitivity should be in the mid to upper 80’s.

The project is nameless at this juncture.

What do you all think?

[---k---]

Dan,
Looks like a nice project with a lot of potential to sound great. You post almost reads like this is going to be some missmatch spare driver, budget design. Hardly, I suspect.

The MDM-55 is a sealed mid, no? So the open baffle look, is really just for looks?

Any reason not to push the tweeter and mid up a bit to be close to the chamfers?

[dlneubec]

The open baffle look is look only. It is partially because it was adapted form an open back (tube or diople) concept I had already done.

The reason the mid and tweeter are lower is CTC spacing. I wanted to keep the lower woofer within 1 wavelength at the crossover. The woofers could be a little higher, but that would compromise the TL design.

This was the original concept that I adapted to this design. It is sort of a short powerful look I was going for.

[HareBrained]

If you're workin' from your own stock, what else do you have available?

I like the 22T over the RS28, especially for a 3-way.

[---k---]

Gotcha. Is the size of the woofer TL accurate yet? The depth just looks huge compared to the width.

Are there going to be any new, unique features to this one? You're Basslines had the tweeter waveguide, and before that you were Mr. Omni. If you like, I'm sure we can find some way to make these much more complicated than a standard 3-way.

[TedG]

A standard 3-way would be a lot easier for beginners to try and duplicate than some of Dan's other more extravagant designs.

[TacoD]

A standard 3-way would be a lot easier for beginners to try and duplicate than some of Dan's other more extravagant designs.

Yup, it starts with some simple sketches and ends up with an impossible cabinet + veneer job. By the way it always looks stunning, I also liked the step by step descriptions of his other builds.

To stay on topic, your x-over points look fine to me. Maybe you need some extra components to get rid of the RS180 breakup. I would pick the TAF22 this will work nicely with the Morel (also the mounting plate is smaller -> closer CTC mounting).

[kevinp.]

Cool concept. Same drivers as Rick Craig's 3 1/2 way 35F, I believe

[BobEllis]

Nice concept. Wish I had your design skills.

Not to discourage you, but I've done a few TLs and have come to the conclusion that other than a ML-TL, it wasn't worth the effort. Pass band ripple and construction complexity are the major downsides. I had some success matching low end roll off to room gain in a small room using 7" drivers, which was nice.

[dlneubec]

If you're workin' from your own stock, what else do you have available?

I like the 22T over the RS28, especially for a 3-way.

See the post below where I give the list of drivers on the shelf.

Gotcha. Is the size of the woofer TL accurate yet? The depth just looks huge compared to the width.

Are there going to be any new, unique features to this one? You're Basslines had the tweeter waveguide, and before that you were Mr. Omni. If you like, I'm sure we can find some way to make these much more complicated than a standard 3-way.

Paul Carmody sort of mentioned the same thing and I told him that all my project start out with me telling myslef that I'm going to keep this one simple, but they end up complex. Quit tempting me! :twisted:

Yup, it starts with some simple sketches and ends up with an impossible cabinet + veneer job. By the way it always looks stunning, I also liked the step by step descriptions of his other builds.

To stay on topic, your x-over points look fine to me. Maybe you need some extra components to get rid of the RS180 breakup. I would pick the TAF22 this will work nicely with the Morel (also the mounting plate is smaller -> closer CTC mounting).

My thinking exactly.

Cool concept. Same drivers as Rick Craig's 3 1/2 way 35F, I believe

Thanks Kevin. I'll have to take a look at what Rick did. I have the the lower woofer within 1 wavelenght at the crossover to the mid so a 3.5way should not be necessary.

Nice concept. Wish I had your design skills.

Not to discourage you, but I've done a few TLs and have come to the conclusion that other than a ML-TL, it wasn't worth the effort. Pass band ripple and construction complexity are the major downsides. I had some success matching low end roll off to room gain in a small room using 7" drivers, which was nice.

Thanks, Bob. I have built a couple TL's and heard a number of them that Paul K. has designed. They always have had some of the best bass I heard at the various DIY meets. Also, you will notice that Jim Salk is several TL's now that Paul has designed, such as his SongTowers and the new HT3. It is my understanding that he wanted to use a TL for those new HT4's, but the bass driver they selected just did not work well in a TL. I think TL's, with the right drivers, offer some of the benefits of both standard sealed and ported designs, with less of the drawbacks. When done right, the upper bass, mid ripple can be easily kept within +-1db, which was the case with this design, but it takes careful consideration of stuffing location and density. You can get lower F3 with more ripple or decrease ripple for a little higher F3. There is always a trade-off. This one has an F3 of about 37hz. The ripples don't really even start until around 600hz or so, are only about +-1db in value (see attached sim) and at that point I should be getting a fair amount of contribution from the MDM55, which should help fill in to some degree anyway.

[dlneubec]

Additional Concepts

Ok, lets up the ante for the fun of it and add more fodder for discussion. These are drivers I have on the shelf that I can work with:

2- TC1000 12” subs
4- 12” PE buyout paper cone woofers, 8mm xmax
2- RSS265HF 10” subs
2- RS225S-8’s
6- RS180S-8’s
2- PHL 2520 8” midranges (100db sensitivity)
2- Focal JM Lab 6VE3251B 6.5” polyglass midwoofers
2- RS150-4’s
2- RS125S-8’s
2- Morel MDM55 2-1/8” dome midranges
2- RS28AS-4 tweeters and a third that needs a new VC
2- Vifa Logic AC25SG05-04 tweeters
2- Seas 22TAFG tweeters
2- Dayton ND20FB-4 tweeters
2- Unknown ½”? metal tweeters (door prize with the Focal JMLabs)
1- Dayton PT2C planar tweeter
1- Seas 27TAFNC/D tweeter
1- Dayton ND20FA
1- Dayton ND16

That’s all I can remember. After that I start to cannibalize completed designs, which I would rather not do at the moment, though the 4 Vifa XG-18’s and pair of 27TDFC’s in my Nao Mini’s are tempting to grab up for a new project, though I would rather sell the Nao Mini’s.

Here are the other design concepts that I have developed for potential future projects:

The first I already showed and was the one adapted to this design. It was intended to be an open back tube midrange, which could also be adapted to open baffle dipole. It could be a WMT or WWMT



This one is a high efficiency 2way using a pro woofer waveguide and compression tweeter with some poly carbonate mixed in to the look.



Next up is another open back mid concept with room for a largish woofer on the bottom end. It could also be a WWMT.



Then we have a more traditional box (well not really traditional). It is the most flexible and could be open back tube or sealed mid and WMT, WWMT, WWMTM, etc. depending on the height.



Finally we have a WWMT design that was intended to potentially have open baffle 15” woofers, midrange and possibly even the tweeter. The bass drivers could also be boxed. It is about 18” wide at the widest and 48” tall.

[ttan98]

My open baffle looks like your last system from your pictures(above) you drew up, ie my config. is Ribbon, PHL mid and Uframe with twin 12" woofers. Sounds good too. So far I use a compression driver(with B&C horn) instead of ribbon(still waiting for arrival).

[Johnloudb]

I like the first design concept. Looks like some kind of a cannon Royalty might have used. Ha, Ha ... it's the most pleasing from an aesthetic point of view IMO. Give it's size it really should have a 10" or 12" woofer, like your TC1000 subs or your RSS256HF subs. An RS150 or RS125S or PHL2520 for the midrange. I also like transmission line bass. :T

Seas or Vifa tweeter. I don't know, just which ever tweet would work best. This speaker should be Powerful. Anything with wimpy bass or something that wimps out on loud dynamic passages, just wouldn't cut it for this design. Just my subjective thoughts.

[dlneubec]

I like the first design concept. Looks like some kind of a cannon Royalty might have used. Ha, Ha ... it's the most pleasing from an aesthetic point of view IMO. Give it's size it really should have a 10" or 12" woofer, like your TC1000 subs or your RSS256HF subs. An RS150 or RS125S or PHL2520 for the midrange. I also like transmission line bass. :T

Seas or Vifa tweeter. I don't know, just which ever tweet would work best. This speaker should be Powerful. Anything with wimpy bass or something that wimps out on loud dynamic passages, just wouldn't cut it for this design. Just my subjective thoughts.

Hi John,

Well, if I wanted to complicate things a bit, I could go to a 4way with either the TC1000's or RSS265HF's as subs to 80-120 hz or so using a plate amp for the xover, maybe sealed for smaller box size, then the 2-RS180's sealed rather than TL, in about 12L and the MDM55 and 22TAFCG as planned.

Actually, I have about 56 liters in the cabinet as it is. To use the RSS265HF, for example, I'd have to widen it at least an inch, which would up the volume to 63 liters. Take 12 off for the sealed RS180's and you have about 50 left, which would model very well for the RSS265hf's ported. 8O

[BobEllis]

... I think TL's, with the right drivers, offer some of the benefits of both standard sealed and ported designs, with less of the drawbacks. When done right, the upper bass, mid ripple can be easily kept within +-1db, which was the case with this design, but it takes careful consideration of stuffing location and density. You can get lower F3 with more ripple or decrease ripple for a little higher F3. There is always a trade-off. This one has an F3 of about 37hz. The ripples don't really even start until around 600hz or so, are only about +-1db in value (see attached sim) and at that point I should be getting a fair amount of contribution from the MDM55, which should help fill in to some degree anyway.

Doh! I was doing two ways back then, so my passband was much wider ops: . The drivers and tuning I tried didn't do nearly as well as your sim, showing several dB of ripple. Good luck with it.

[Brian Walter]

Not that it matters, but Rick Craig from Selah Audio has a design using those same drivers (2-RS180's, MDM55 & 22TAFCG). I built a sealed version of the center channel to go with my RS-WWMT and it sounds awfully nice. I think a sealed combination teamed up with a bass bin would be really nice.

Brian Walter

[dlneubec]

Hi Brian,

Someone else mentioned that Rick had a design using the same drivers. I will have to look at it.

The sealed RS180 version with sub bass bin is an intriguing one and I'm playing with that concept right now (see below). The trouble with it is that if I use the drivers I have, it probably means I hav to add plate amps as well (which I do have) and with subs and plate amps, the price of goes up by about $500 for anyone contemplating building them.

By all means, I'm perfectly satisfied with my BaSSlines and I don't see these or any other design I can do with the drivers I have available ever replacing them, so I'm doing it for the fun of it and in case someone else wants to build them.

[HareBrained]

Thanks for the list of drivers.

I've read elsewhere that the 180 is a surprisingly good TL (as is the 225). And by that I mean, it will exceed expectations even if they're already high.

I would have preferred to see something other than the MDM55 for mids but I don't see anything "reasonable". So, I'm voting for the original concept.

[cjd]

RS225, MD55, one of the ND20 tweets. Let the TL breathe, you should be able to hit low 30's on extension I think.

RS265/RS150/RS28A is another sweet combo tho the RS265 would probably be active. Could also use the TC sub instead of RS265.

[dlneubec]

Hi guys,

Here are couple more options:

The RSS265HF is in about 65l with a 24" slot port, powered by the 240w dayton plate amp. The box is tuned to about 23hz for an f3 of about 20hz, and gets to about 106db before reaching excursion limits at 200w. I had to close in the back top section to get the bigger volume.

The RS180's are sealed. Crossover to the RSS265 in the range of 80-120hz. I would expect the sensitivity to be in the range of 87-89db, depending on BSC, etc.

The speaker is still pretty small at 11" wide, 42" tall and 26" deep at the plinth (box is 18" deep)



I have one other project I'm considering along against this one. It would use one of two combo's and would be based upon the concept I posted that is kind of pyramid shaped, very narrow at the top for the tweeter and uses an open backed tube for the midrange. Both concepts would use the TC-1000 as a woofer, probably crossed in the 300-400 range. The mids would be either the 8" PHL 2520 or I would dedicate my Duo cabinets to the Duo-T, which would free up a pair of Scan Revelator 15W/8530K01 for mids. The latter might be a little lower sensitivity design, but with the additional xmax that the TC-1000 and those little Scans have that might not be ok.

Pulling the drivers from my Duo-S project would also free up a pair of vifa D26nc55 neo tweeters to use in one of these projects. I'm not sure if this pyramid concept would use the RS28's or perhaps the Vifa D26nc55's, since I could get them very close to that 8" mid, maybe doing a shallow waveguide mount for them like in my Duo's and BaSSlines. I already know that the scan and vifa can work well together from using them in my Duo-S design. I'm thinking all passive on this concept, since the Tc-1000's appear to be in the 88-89db sensitivity range.

The TC-1000-PHL 2520-? tweeter might look something like one of these. I've yet to work out the option with the scan 15w mid:

[---k---]

Now were getting somewhere!

While somewhat traditional looking, I like the look of the 4-way. We don't see enough 4-ways. It should be a very capable speaker. Are you think all passive crossover or active for the RS265?

I would hate to see you pull apart previous designs to make this one. Have you given any consideration to selling your existing designs instead? Probably difficult to sell and you wouldn't get what they are worth. But it would be better than making them completely worthless by pulling the drivers from them.

[ttan98]

I used PHL 2450 8"(about 93dB spl and Fs=80 hz) as a mid woofer in an open baffle configuration, they sounded very good too.

I am not familar with PHL2520 model. Maybe you might to to try to mount this driver in U-frame config.(with fillings), similar to the mid used in The Beast from Salk.

[dlneubec]

Now were getting somewhere!

While somewhat traditional looking, I like the look of the 4-way. We don't see enough 4-ways. It should be a very capable speaker. Are you think all passive crossover or active for the RS265?

I would hate to see you pull apart previous designs to make this one. Have you given any consideration to selling your existing designs instead? Probably difficult to sell and you wouldn't get what they are worth. But it would be better than making them completely worthless by pulling the drivers from them.

Yeah, it is a little traditional looking for my tastes at the moment anyway. I would be going active with a plate amp, crossing at 80-120 hz and maybe using a highpass on the RS180's as I did with the HOSS and RS150's. I'd lose too much sensitivity to go all go all passive, I think. It's very early in the process however.

I'd like to sell some of my designs, but I have not given it a lot of thought or attention. They are rather unique and probably have a small maket for that reason.

I used PHL 2450 8"(about 93dB spl and Fs=80 hz) as a mid woofer in an open baffle configuration, they sounded very good too.

I am not familar with PHL2520 model. Maybe you might to to try to mount this driver in U-frame config.(with fillings), similar to the mid used in The Beast from Salk.

The 2520 is spec'd at 100db sensitivity.

It is my understanding from Jim and Jeff that he is essentially using an open back mid, the same thing I'm using here. I will have to experiment and measure to adjust the length and filling, though it might be modeled with TL software like Martin Kings. We'll see how this goes forward from here. Jeff has also informed me that the 12" driver used in that design is very close to the same as the TC-1000 I have and they had no problem crossing it at 400hz 2nd order, so a passive is a very good possibility, though the PHL would have to be heavily "sedated"!

[ttan98]

The 2520 is spec'd at 100db sensitivity.

It is my understanding from Jim and Jeff that he is essentially using an open back mid, the same thing I'm using here.

Open back is like a "quasi or pseudo" U-frame. The sound is dependable on the length of the open back and also the material you put behind the back. I have tried the length bit not the material used. FYI Gary P. uses an open back on his mid as well with fillings and he is getting very good results.

Anyway all the best in your testing.

[dlneubec]

I might be able to model it in ABCDipole as a U-frame or as a TL as mentioned. I will probably try both, compare the results and then go from there.

The most notable open back design here on HTguide is of course the Statement series. I know Jim and Curt had to do a bit of testing of stuffing, crossover changes, etc. to get that just right, so I expect to have to do the same.

[Hdale85]

This looks amazingly interesting to me

[Johnloudb]

I agree with Ryan. I like that big speaker. The speaker with the transmission line mid "cannon" is still my favorite from an aesthetic perspective. But the four way design definitely has it's own charm, and more practical. You seem to have a real talent for coming up with these artistic and innovative ideas.

[Johnloudb]

Like Dougie just said when he beat my last post!

This looks amazingly interesting to me

[Hdale85]

Although I did kind of want a Scanspeak mid in my next build haha.... but that one could be a possibility.