Full-range in walls...

[speakrsrfun]

I have a question for anyone who has built their own in walls. I have a friend who purchased 8 CHR-70's for the purpose of a boxed HT system. WIFE told him absolutely no to the boxes and I suggested making them into in walls and building the cabinet volume into the stud wall. I believe Parts Express makes empty baffles for in walls so it could be as easy as mounting a prefab setup to a built in box. I understand that the wall is going to cause some issues but assuming he's allowed to do this instead of BIG boxes as she put it (Jeez she'd hate to be my wife) in the living room, we would have series ran CHR-70's for the three front channels and a single driver for the rears.

Anyone ever attempt anything like this? I currently have a 5.1 full-range system that sounds fantastic and had hopes we could go this route with his CHR-70's.

Any idea's or thoughts welcomed....

[preiter]

If you are talking about putting boxes in the walls, then no problem. The only thing that changes is that there will be no baffle step to deal with. Then again, the CHR-70 is voiced to include some baffle step compensation, so your highs might seem slightly recessed compared to a traditional box.

If you are talking about just mounting the driver on a baffle and leaving the back open to the space inside the wall, then you are in a configuration called infinite baffle and you need a driver suited to that application.

[speakrsrfun]

I understand the fundamentals of design when it comes to driver choice and box design, I guess I'm asking more from a HAS ANYONE DONE THIS type route. I just wanted to re-enforce my understanding of wall interactions and the fact that these may be a tad bass heavy as an in wall, but crossed at 80-100Hz should be well suited to the job. Thanks for the re-enforcement preiter it helped.

[Cal Weldon]

The q is high enough you might get away with just mounting them in the walls.

These will never be a tad bass heavy, they're a tiny little driver.

If you are cutting them off at 100 hz, neither of the above 2 statements applies. The only concern is to mount them to something solid. If you are mounting in a stick frame, your walls are likely 16" or 24" OC. That's quite a span from a WAF perspective. How are you planning to secure them?

[speakrsrfun]

Originally Posted by Cal Weldon

The q is high enough you might get away with just mounting them in the walls.

True...

Originally Posted by Cal Weldon

These will never be a tad bass heavy, they're a tiny little driver.

Sorta true maybe bloated is a better term rather than bass heavy.... I've heard these little drivers in some different cabinets and they can sound bass heavy and bloated if not implemented correctly.

Originally Posted by Cal Weldon

If you are cutting them off at 100 hz, neither of the above 2 statements applies. The only concern is to mount them to something solid. If you are mounting in a stick frame, your walls are likely 16" or 24" OC. That's quite a span from a WAF perspective. How are you planning to secure them?

16" centres in most homes by code in Ontario are required but that's not to say people don't build otherwise.... First, Removal of drywall around mount point, mount plywood cabinet to studs flush with framing with screws and PL adhesive and precut for baffle cutout before remounting drywall to the studs again and gluing the drywall to the plywood box. Then using your drywall saw or rototool cut out the baffle hole and mount the prefab inwall baffles with good screws and some weather striping. That should be sturdy enough and all ports if needed or wanted can be mounted to the baffle and extend into the box. Re-mud, sand and paint and she's happy, she doesn't want the boxes and the compromise is a bit of dust...

I'm just trying to get a friend some decent sound without divorce... LOL.

[Cal Weldon]

Sounds like you have it well under control.

I too have heard the different versions of the drivers and I guess our opinions are what makes us individuals.

We still have 24" for non-bearing interior walls.

Cheers.

[markaudio]

Hi Guys,
Please note the changes in total Q between the Gen. 1 CHR-70 at 0.65 going down to 0.547 for the CHR-70 Gen 2. The generation 2 driver is the current model. Gen 1 drivers are now mostly out of stock at many dealers.

Full specs are on these web pages:

CHR-70 Full Range Driver | Markaudio
CHR-70 (2010 Revision) | Markaudio

Cheers

Mark.

[SoundmanDave]

There are well-priced in-wall speakers available that come with the correctly engineered back boxes and baffles and mounts and all that. Tannoy is one that comes to mind first. They also have matching in-wall subs if the wife really wants the speakers to disappear.

I would go this route simply because you are not messing with a good set of speakers to 'make it work'. I'd keep the other drivers that you have for another project where they can be used as intended.

That said, you have the right idea. If you are allowed to open up the wall as much as needed, you could frame in a correctly sized space in the wall and use some anti-vibration material on the edges of the studs before drywalling. This will help make a better air-tight seal and keep the wall boards from vibrating loose and rattling. I recommend a good epoxy filler to make the whole thing seal right as well, obviously you will be designing a sealed enclosure so it would be good to cross it a little higher, maybe 120-150 and let the sub do its thing.

Interesting that the wife would rather have the room torn apart to put speakers in the walls than to have boxes in the room...