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Coaxials: Another DIY Group Project.

230K views 2K replies 261 participants last post by  mtg90 
#1 ·
About 4 years ago one of the AVS forum members started a few polls to gauge people's interest in a group effort coaxial speaker, or a waveguide style set up. It was roughly a 50/50 split on what should be designed. In the end it shifted towards the waveguide speaker, which eventually led to the SEOS project getting started here on AVS. That project was a big success with new waveguide designs, cheap speaker kits, etc. More will be coming of course.


But maybe we should also go back and update the coaxial project. After a few more polls on the end design, members couldn't narrow it down to one specific model, and the project faded away. So what about working on a few different set ups and enclosures over a wider price range?


I'm open to any suggestions except one: I don't want to work on any active crossover designs that compete with Mark Seaton's speakers.


There are a couple small projects done or being worked on, like the 8" and 10" Eminence coaxials. But if anyone has suggestions on what type of layout or what other models to try, I'll do my best to get the project rolling forward.
 
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#4 ·
Eminence coaxes are pretty poor performing. Try some B&C.
 
#5 ·
What size are you going to? I can suggest the Celestion TF1225CX. It's a 12" with a neo CD. What price point are you after as this will be a little pricey?
 
#6 ·
Would this be for Music or HT....or both?

Seems the wave guide has the HT market tied up,

as it should....so maybe the coax would be more for

primarily 2 ch duty?


Boxed...Open Baffle....something else?


I have a Co-ax OB from Danny Richie.

Its simply amazing.....I can hardly wait

to see what comes from this thread.
 
#9 ·
- an IB design for in-wall or ceiling use for "normal" rooms

- a few levels by cost, ie the v8/10 for entry level, a B&C, Faital, Beyma, etc

- as far as boxes, sealed and ported for standard boxes, and slant at a 45 and 30 degrees

- something for outside that can be used in an 8" wakeboarding tower enclosure


I wonder if John at AE would be interested in working with you guys on building a TD coax using one of the Denovo CDs... that would be pimp. Then there could be a design with that coax and one of the Denovo CDs with the BE upgrade and two of the TD12 for something like the 212.
 
#11 ·

Quote:
Originally Posted by d_c  /t/1514289/coaxials-another-diy-group-project#post_24269447


- an IB design for in-wall or ceiling use for "normal" rooms

- a few levels by cost, ie the v8/10 for entry level, a B&C, Faital, Beyma, etc

- as far as boxes, sealed and ported for standard boxes, and slant at a 45 and 30 degrees

- something for outside that can be used in an 8" wakeboarding tower enclosure


I wonder if John at AE would be interested in working with you guys on building a TD coax using one of the Denovo CDs... that would be pimp. Then there could be a design with that coax and one of the Denovo CDs with the BE upgrade and two of the TD12 for something like the 212.
I wish it was that simple. Plus, it would be nice to have the best of the best.
 
#12 ·

Quote:
Originally Posted by Antripodean  /t/1514289/coaxials-another-diy-group-project/0_100#post_24269217


What size are you going to? I can suggest the Celestion TF1225CX. It's a 12" with a neo CD. What price point are you after as this will be a little pricey?

That one might be interesting, because it comes from a team led by one of the deans of concentric driver design.* However, they don't seem to be widely available.


However, as someone knee-deep in concentric drivers from 3" to 12", I have to say, they're hard. The problem isn't crossover design, which if anything is easier. The problem is that the really good answers to the hard problems, such as mouth termination, are either corporate secrets or locked up as proprietary IP by companies that don't offer drivers to hobbyists. And there are more bad concentrics than good ones.


Honestly when working with readily-available drivers, I don't think the concentric approach is as good as the SEOS approach.


*Mark Dodd, of the Tannoy "Tulip" drivers and the current KEF Uni-Q, is in charge of driver design for KEF/Celestion. The other "dean of concentric drivers" would be Andrew Jones (original KEF Uni-Q, TAD/Pioneer CST, that Pioneer ring-radiator thingy from Pioneer).
 
#13 ·

Quote:
Originally Posted by A9X-308  /t/1514289/coaxials-another-diy-group-project#post_24269132


Eminence coaxes are pretty poor performing. Try some B&C.

I don't know the performance of the eminence. But another vote for any 8inch B&C like 8cxt or B&C 8CXN51. passive crossover of course

Slant boxes for surround because no option for surround speaker available and it can be use as height. Thanks
 
#14 ·
I have a B&C 8CXN51 on the way for a project that I'll be doing very soon. Looks to be the best of the bunch for B&C. I was going to do a stand mount 2-way, with several crossover versions for a standalone unit and one that would be intended to cross to a woofer, and in both active and passive versions. I'd really like to compare these to the best of the Beyma and FaitalPro offerings.
 
#15 ·

Quote:
Originally Posted by DS-21  /t/1514289/coaxials-another-diy-group-project#post_24270074


That one might be interesting, because it comes from a team led by one of the deans of concentric driver design.* However, they don't seem to be widely available.


Honestly when working with readily-available drivers, I don't think the concentric approach is as good as the SEOS approach.

I can get the drivers, just need to make sure I order enough. If someone really wants to go there I could organize a sample. I can find out more details from GPA as well.


However, I agree the WG approach should be better.
 
#16 ·

Quote:
Originally Posted by Antripodean  /t/1514289/coaxials-another-diy-group-project/0_50#post_24270970


I can get the drivers
Depending on the price I'd be interested in a pair.
 
#17 ·

Quote:
Originally Posted by DS-21  /t/1514289/coaxials-another-diy-group-project#post_24270074



That one might be interesting, because it comes from a team led by one of the deans of concentric driver design.* However, they don't seem to be widely available.


However, as someone knee-deep in concentric drivers from 3" to 12", I have to say, they're hard. The problem isn't crossover design, which if anything is easier. The problem is that the really good answers to the hard problems, such as mouth termination, are either corporate secrets or locked up as proprietary IP by companies that don't offer drivers to hobbyists. And there are more bad concentrics than good ones.


Honestly when working with readily-available drivers, I don't think the concentric approach is as good as the SEOS approach.


*Mark Dodd, of the Tannoy "Tulip" drivers and the current KEF Uni-Q, is in charge of driver design for KEF/Celestion. The other "dean of concentric drivers" would be Andrew Jones (original KEF Uni-Q, TAD/Pioneer CST, that Pioneer ring-radiator thingy from Pioneer).
if the seos is better than any coaxil design... why isnt mark seaton using waveguides? his monitors are far superior compared to a seos. of course, a lot more expensive to. like others, im interested in a design very similar to mr. seaton's design
 
#18 ·
I agree with a lot of the comments here. Coaxials are tricky little things. And as DS21 mentions, the good ones aren't available to DIYers. Having said that, I've always thought an 8" coax with an 8" 1/2 way woofer would be a really cool speaker. It would be 9x18" and look pretty unit. Maybe even high pass the coax to make it a 3 way if cone modulation affected the tweeter response to much. That can be extremely critical with coaxials, which is something I haven't seen discussed all that much.
 
#19 ·

people put their heads together and design a 2-way coaxil.... mark is in trouble. most of the money going in to his monitors are the built in amps with dsp. im sure we could score those coaxils some kind of way. i listened to a pair of mark's monitors at danely's studio. they will blow your mind! crystal clear and awesome for music and ht.
 
#20 ·
id vote for something small. like a 6" that can produce big sound.


sure most of us are all about HT and that space is pretty well covered, i run the v8s on my computer currently but something smaller that could act as a pair of 2.0/2.1 bookshelfs in smaller spaces would be amazing
 
#21 ·

Quote:
Originally Posted by MD28  /t/1514289/coaxials-another-diy-group-project/0_100#post_24271662


people put their heads together and design a 2-way coaxil.... mark is in trouble. most of the money going in to his monitors are the built in amps with dsp. im sure we could score those coaxils some kind of way. i listened to a pair of mark's monitors at danely's studio. they will blow your mind! crystal clear and awesome for music and ht.

i dissagree there is a huge divide between those willing to buy acomercial product at that level and those who DIY.
 
#423 ·
Quote:Originally Posted by MD28 

i dissagree there is a huge divide between those willing to buy acomercial product at that level and those who DIY.
There is a financial chasm.

The combination of the ability to hear the difference AND be able to prioritize cash for a commercial product of such quality is becoming more rare. When was the last time a barista or pizza worker earned the value of 8 gallons of refined fuel per hour or an ounce of gold a week on a steady basis? A. 2002 (good times, btw.).

I've enjoyed my C35 KEF Uni-Q bookshelf speakers since college. The upgrade path was better passive crossover, external analog bi-amp, then DSP bi-amp (steady rotation of amps, all
 
#22 ·

Quote:
Originally Posted by Sibuna  /t/1514289/coaxials-another-diy-group-project#post_24272045



i dissagree there is a huge divide between those willing to buy acomercial product at that level and those who DIY.
but... why compromise? mark's monitors are just efficient and sound better. why not beat him at his own game. why settle for less?
 
#23 ·
I think Sibuna meant Mark's products wouldn't be in trouble cause a lot of people just won't DIY. Erich doesn't want to do something that directly competes, because Mark is a friend around these boards, and it's already been done. If that's the kind of speaker someone wants, they should just by Mark's. It's a great product already at a great price, no DIY required. I gotta agree in that, as an engineering excersize, doing what Mark has already done isn't that interesting. He's already blazed that trail and done it really well.


Doing speakers that are similar is interesting. Like the 8" coax with an 8" woofer that I mentioned. Or in the same vein as the JTR triple 8, but very budget friendly using cheap eminence woofers and a cheap coax and passive. Could be a useful design. But I don't really have a good handle on the commercial market and what's available...
 
#24 ·

Quote:
Originally Posted by MD28  /t/1514289/coaxials-another-diy-group-project#post_24272086


but... why compromise? mark's monitors are just efficient and sound better. why not beat him at his own game. why settle for less?

I'm not sure the goal here is to beat anyone, just have lots of fun and develop great designs. I do question the above argument though, that if the seos were better, Mark S would use them....or that Seaton speakers are better than anything the that could be built with a seos wg. Mark is a great guy and I like him alot, but just because he doesn't use a particular method doesn't mean it's not better, or have the potential to be as good. That's like saying becuase Mark doesn't use a Synergy horn design like Danely, Seaton speakers can't compete. I have also had conversations with Mark where he has clearly stated his intention of developing something using a simalr WG. All that said, Marks' speakers are world class IMHO. Not being confrontrational at all, just playing the other side. I love both the seos based designs and Marks' designs.


I agree on another front though...why compromise?? What Erich has done at diysg is fantastic and I believe the market for real budget based diy is long lasting. What I also believe is that there are quite a few diy'ers out there who don't diy for the budget, but to see how far it can be taken. I'd personally like to see a few designs that don't just say "lets see how good we make this $89 coax with $30 in xover parts", but how good a speaker can we develop at higher price points. I know that there is no desire at diysg to compete with those guys and I admire that, but I think we need to remember one thing..most who will attempt that level of a diy project aren't purchasing a finished product from them anyway, or are purchasing it anyway to compare and have some fun. Heck, I'm doing that right now with a set of Danley SH50s and my seosr that aren't even finished yet.


Beast's Beyma is doing just what's described above...pushing the envelope a bit more. Instead of saying, does this $150 solution sound good enough, he's said "what can I make that I'll like better than a single 8?" If it costs half great, if it costs the same, but one prefers it to the other, great still. The thing that diysg has going is that it isn't a bunch of hacks like me
, trying to figure out how to make speakers work, it's a bunch of accomplished and talented designers who can make some really good stuff. I'd like to see both ends of the spectrum at the diysg. Mtg is a great example...he can design a $100 build that people will like and buy and get them in the HT game, but he can also build a speaker with a couple grand of components that kicks a$$...I'm confident based on where I'm at with my custom build (which he designed the network for), that the best components available in the hands of these guys will make diysg a company that can offer a product to fit any enthusiasts needs.
 
#25 ·

Quote:
Originally Posted by Sibuna  /t/1514289/coaxials-another-diy-group-project#post_24272024


id vote for something small. like a 6" that can produce big sound.


sure most of us are all about HT and that space is pretty well covered, i run the v8s on my computer currently but something smaller that could act as a pair of 2.0/2.1 bookshelfs in smaller spaces would be amazing

There is a 6" model in the works, possibly 2. I'll get more info up on those later.
 
#26 ·

Quote:
Originally Posted by ChopShop1  /t/1514289/coaxials-another-diy-group-project#post_24272280


What I also believe is that there are quite a few diy'ers out there who don't diy for the budget, but to see how far it can be taken. I'd personally like to see a few designs that don't just say "lets see how good we make this $89 coax with $30 in xover parts", but how good a speaker can we develop at higher price points.

I think you're right that a lot of DIY'ers do build with this mentallity. But where I see a problem is that this doesn't relate to DIYsoundGroup in any way (Erich can correct me if I'm out to lunch).


1. The group buy funds can't support such extravagent builds;

2. Builds like this deserve complex in-room measuring and consideration of the room;

3. 99% of the time they're active;

4. The most important, at this level, everyone has their own idea of what the speaker should be. Regarding the SEOS24, you chose 4 x 15" AE woofers. Face chose 2 x 15" AE woofers in a cardioid box. If I did something like that, I'd use 4x18" B&C woofers, two of which would b in separate boxes for placing in corners. And on it goes. All using the SEOS 24, but all so very very different.


It's hard to make a one speaker fits all at that level of DIY. Especially since about 10 a year would sell. The Catalyst would out sell it by miles, because it's a commercial product and doesn't require a crappy paint job.


If someone wants to build a wicked no compromise high end build, they should DIY, or ask someone with the design chops to help them, like you did.
 
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