Coaxial Drivers

[madbrayniak]

Hello all,

I have a very high interest in Coaxial drivers and I was wondering if anyone knows of any good resources that I should look at?

My system is a dual purpose system for music and home theater and since I like the tube sound I like have high sensitive speakers.

I have always been interested in the Tannoys and other point source approaches and so I think I am going to try to DIY a pair of speakers.

I am sure some of you have seen the Mark Seaton and JTR speakers that are available and I plan to kinda take from what they did as a reference point.

From that I have found that Faital Pro 8HX200 to be a very interesting 8" coax.

Other than that RCF has some very interesting 12" coaxials with the HF having a full horn. Will that horn cause any issues with the midrange?

If I go with the 8" it is pretty much a sure thing that there will be another driver in there to keep the 8" from working too hard and muddying up the midrange.

Anyways, my question is, does anyone know of any good resources about coaxial drivers and designing cabinets for them?

does anyone here have any experience with them or Tannoy Prestige speakers?

[johnsonad]

Great Plains Audio 604's. There is a half centuries worth of great boxes out there for them and I never met a 604 that I hated.

[Tubejack]

If you are willing to consider OB configuration, I have been very pleased with the Hawthorne Sterling Silver Iris + Augie Duet configuration; using 300B SET's on the SSI's and 200W SS monoblocks on the Augies.

http://hawthorneaudio.us/

[Mike B]

I use Eminence Beta 10's with Selenium D220Ti horn drivers in my garage system.

Good effeicency, can get very loud.

[madbrayniak]

This is the particular RCF that I was looking at.

http://www.rcf.it/en_US/products/precision-transducers/coaxial-transducers/cx12n251

With the 12" COAX I would be doing something with maybe dual 12 so it would be the coax down to like 80hz and then have a second 12" woofer to take it lower.

Here is the 15" version that could also be good.

http://www.rcf.it/en_US/products/precision-transducers/coaxial-transducers/cx15n351

This would essentially be just the 15" driver in a large monitor like enclosure like you used to see with the old Altec 604.

[Paul Birkeland]

It will take a lot of work on the crossover to smooth that out sufficiently for home use, but they may sound great thereafter.

[Clark B.]

I have to second the GPA recommendation of Aaron's.  I made this pair of speakers several years ago, dubbed "Josephine," after an old ragtime tune I've got on 78. 

It used the GPA 212-8A and they had nice sound even from the stock crossover once they were broken in.  I ultimately concluded that if I worked with coaxes again it'd be the 604 from GPA. 

The 212 had a rising response up to 16k that bothered my young ears, and from peripheral experience with the 604 I gather that its a bit smoother, but still needs some smoothing in the 2-4k region to work truly well.  (That anomoly was something that old studio engineers trained themselves to actually "listen through," funny enough. 

All that said about the 604, I have kept in touch with the customer for the Josephines over the years and he says they've just gotten better an better over time.  Also, the staff (Bill) at GPA was a pleasure to work with. 

I do have to go on record to say that I've heard a fair share of Tannoy's all the way down to their $600/ea studio monitors and all the way up to the Westminster Royal HE's and even their new $60k offering.  Though it is a nice point source, and decent all around, they've just never been my cup of tea.  The Altec style coax design has it down.  the 604 was the most sold studio monitor driver until the mid 70's IIRC.  The GPA's are very well made I believe on alot of the original Altec tooling.

Cheers!

-Clark

[madbrayniak]

Would you guys say that the Coaxial drivers with integrated horn are better than the tannoy approach on average?

My biggest concern about the coaxial drivers that use the woofer as the horn is that the cone moving will cause too much IMD distortion to the sound.

However, One thing I have considered is that I can use a second woofer of the same size to cross a little higher to try and keep that coaxial from working too hard and keep that distortion to a minimum.

[johnsonad]

First I would say get out and listen to these speakers for yourself; theory is no substitute for your ears at least for the production speakers like the Tonnoy's. it shouldn't be to hard to find local 604's either.  Second I would put a moderate amount of faith in the engineers who designed a few of these drivers. For example, the 604 has been in continuous production since the 1940's and they are still selling them. They must have gotten something right

[Clark B.]

Would you guys say that the Coaxial drivers with integrated horn are better than the tannoy approach on average?

My biggest concern about the coaxial drivers that use the woofer as the horn is that the cone moving will cause too much IMD distortion to the sound.

However, One thing I have considered is that I can use a second woofer of the same size to cross a little higher to try and keep that coaxial from working too hard and keep that distortion to a minimum.

Yeah, rereading my post I realize now that I didn't clearly enough state the way I was comparing the different drivers.  The Altec approach (actual horn inside of woofer) has always sounded better to me than the Tannoy approach.  But then again, I might have just never heard the Tannoys done right...

Also, I do prefer the sound of the 604 to the 212.   I think the majority of this is the horn, as the woofers are both fantastic.  also, the 212 could always just be EQ'ed to be flat up top.  Same as the 604 can be EQed to be flat from 2-4k. 

Now as to the reason behind my preference of the full horns (Altec) as opposed to the woofer cone-as-horn (Tannoy), I just couldn't tell you the physics behind the reason for that preference, though it does seem to be a very consistent pattern of my own personal and purely subjective preference.  And of course, your ears might be different.  I really have to second Aaron's recommendation to go and listen to as many as you can.  All the different coax designs out there sound much more different than alike in my personal experience.

Cheers!

-Clark

[jdm]

The GPA 604-8H-II in a 9 cu ft vented box works well with 300B Paramounts in my 11.5 ft x 18 ft room.  As Clark mentioned the crossover needs to provide EQ for the peak in the 2-4k region.

Jim

[madbrayniak]

Awsome,

I do plan to try and find some to listen to before I buy anything.

I have really just been trying to find out which design has the most compromises.

In my own eyes, I think the coaxials with horn would have less issues but I wanted to make sure that my thought process was correct.

after the 604 was mentioned on here I started doing some more digging and it certainly has quite the following on in the audio community.

[madbrayniak]

P.S. if anyone knows someone in the central valley of CA that has some please let me know.

[Mike B]

I am here in the central valley of CA, but have no 604's

I do have what I mentioned and if you want to hear it let me know.