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Wavne 30th March 2010 07:46 PM

CHR/EL 70 cabinet decision
Hi All;
I'm new here (been a lurker for sometime though), and I'm asking advice for choosing a cabinet to build for either CHR or EL 70. The Fonken 167 also appeals to me a lot.

It is for mains for a home theater setup. The amp to be used will be my new gainclone (Audiosector kit)mono blocks configured in parallel. I'm currently running subs but will be building some new ones (Bill Fitzmaurice Tuba 18)as well. I'm planning to do the mains speakers first.

My receiver is an Onkyo Integra 40.1 it has configurable crossover and EQ for mains, center, and surrounds. It also has a bi-amping option for the mains, and pre-outs for all channels.

I'm hoping to build something that is 4ohms and will go down to at least 80Hz. I can configure the crossover to go lower, but I can't configure the subs to crossover above 80Hz. Cost is a factor as well.

Any advice is much appreciated.



italynstylion 30th March 2010 08:22 PM


Do you have any space constraints? Is there a reason you're wanting to build something 4ohm or would an 8ohm speaker do well for you too? Seems like you have plenty of power at your disposal. The dual driver designs would be best for you since you'll likely be running them quite loud and expect decent bass response since they'll be mains.

I've experimented with both the CHR70 and the EL70 in similar dual driver styles. I've tested the Thirlmere bipole and the Coniston^2 designs for the EL70 and the Lotus^2.

All three of the designs are extremely usable below 80hz but do well crossed over 80hz if you're going to be running them loud with a sub. Thirlmere bipole is more finicky about placement so it might not be the best choice. The Coniston^2 and Lotus^2 designs were very impressive and were my favorite to date. It was almost a year between building the Coniston set and the Lotus set so I'm not quite sure I could say which I liked better. I'd love to have heard them side by side.

After the breakin period the EL70 should have a little bit better HF response and sound a bit more natural. The CHR70 is very accurate though and I think the new cone profile design will yield similar HF response to the EL. Here are links to the plans of all 3 and pictures of the ones I built.

Wavne 30th March 2010 09:07 PM

Not really any space constraints. 4ohm because that's how I configured it (the chipamps). I can use 8ohm as well but if I can find something in 4ohm it is preferable.

Thanks for the advice and pics, I will definately check those designs out. Your speakers look great! - and yes, LOUD is how I like it.

planet10 30th March 2010 09:34 PM

The MA drivers will be a better match to either of your amplifiers.

Both the MA drivers are capable of going quite low so 80 hz is a breeze. Relieved of anything below 80 Hz, they will play louder... still, a pair (or even quad) of drivers per side would let the drivers loaf more . A single would be 4 ohms, a pair 8 ohms, a quad back to 4 ohms.

There are lots of box choices for these drivers, if you only need 80 Hz the need for the big boxes are not really needed. I've not heard Coniston^2, but i can say that the primeSize miniOnken, the Mar-Kel70, is stunning, and unassisted, they play pretty loud (for me) in my BIG room. With EL70eN of course. If there is interest i could come up with a 2 driver version, giving something similar to Fonken167 visually -- Bob brought a dual driver BR to the diyFEST last year, no real loss due to 2 front firing drivers.

How exactly are your GC configured? 2 channels per side, paralleled? What are the rails?


Wavne 31st March 2010 12:55 AM

Thanks Dave.

When you say MA you mean Mark Audio? CHR-70?

My GC is paralled which is why the 4ohms, 31 volts per rail. I don't mind running in bridged just that I don't have a balanced source. I am pretty open to configuring the GC to whatever is best suited to the speakers. My current speakers are 8ohm Polk RT 400's.

My subs are a pair of 18" Peavey PA subs running through a Joe Meek SixQ Channel strip to a Peavey GPS 2600 amp bridged. They don't sound great but that's what I got for now. I don't use the subs for listening to music just for movies.

So, I guess if I have options I would prefer a design that will go low for music. Easy to change crossover for movie watching.

I would have a lot of interest in a 2 driver version (visually) of the Fonken167!



planet10 31st March 2010 02:10 AM


Originally Posted by Wavne (
When you say MA you mean Mark Audio? CHR-70?

Yes. Both the CHR70 & EL70 are made by Mark Audio. The latter were made for Bob so have his label. I also got some of those to treat and put my label on.


My GC is paralled which is why the 4ohms, 31 volts per rail.
That might be a little high a rail to just use 2 channels/side each to drive 1 of 2 drivers.


So, I guess if I have options I would prefer a design that will go low for music. Easy to change crossover for movie watching.

I would have a lot of interest in a 2 driver version (visually) of the Fonken167!
I haven't had a chance to measure them, but i'm gonna guess the Mar-Kel70 get into the 40s. I'll get to work on the squared version.


chrisb 31st March 2010 05:36 PM

lemme ride my current hobbyhorse:

"Castle" version of dual driver Microtower (the lighter Cinnamon Cherry veneer pair displayed herein)

not a tough build (certainly easier than the floorstander Fonken167s), very small footprint, and in at least one household, very high WAF

Wavne 2nd April 2010 12:13 AM

Looking around for wood today. Specifically Baltic Birch was what I was looking for as it seems to be recommended. Couldn't find any, but I did find just Birch plywood - will that do? or what about maple?

planet10 2nd April 2010 01:59 AM

What you are looking for is void free plywood with as many plies as possible (the BB we use has 13 plies/18mm, 11 plies/15mm, 9 plies/12mm.


Scottmoose 2nd April 2010 07:36 AM

We can't really get 'proper' Baltic Birch ply over here either (not without a lengthy struggle and paying a fortune) but the standard birch ply is usually pretty good & it's very rare to find even a tiny void in it. Can't speak for what you can find locally of course, but I suspect it's going to be the pick of the bunch, and I'd certainly go with it over the maple (usually more plys as Dave mentions) or MDF (which kills you, and is sonically inferior due to its lack of stiffness / higher density).

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