Axiom Home Page Forums General Discussion Home Theater In-wall or in-ceiling speakers

Spiff,

I can't believe those prices! I guess I better get together with Ian and see if we can't come up with something that sounds better at half the price or less. But the problem remains, if the speaker goes into the wall--not on it or protruding somewhat (to avoid the potential colorations added by the wall)--then the overall sound will be determined more by the area of the wall surrounding the in-wall speaker and the room than by the speaker itself. I think most of these manufacturers are bending to the demands of custom installers. Custom installation is a big (and very profitable) part of many retailers' businesses, so they pressure the speaker companies to produce an in-wall line.

Regards,

Hmmm.. sounds like there are plenty of opportunities for experimentation there Alan. i wonder if any of the companies that have tried this in the past have tried to remove the colorations by flush mounting the drivers, and using a molded face plate that could slightly deflect or refract the sound waves as they come out. I'm picturing a small (1/8" - 3/8" tall) "mountain range" type of arrangement encircling the driver on the face plate to "ease" the offending sound waves away from the wall in a controlled manner. There has to be something that can be done to alleviate the effect of the wall.

I wonder if anyone has tried making the entire face plate concave, (either rounded like a salad bowl, or flat like the inside of a funnel) and mounting the driver slightly behind the wall.

Alan, I'd just like to underscore Michael's point that Axiom seems well-positioned to use its expertise and reputation to broaden its product offerings in this area. If you built this type of product, many existing owners would find a use for it and prospective customers would be drawn by your established reviews in traditional speakers.

Michael, mounting the drivers behind the plane of the wall would probably sounds worse than mounting them a bit forward of the plance of the wall.

Here's a great java animation to give you a visual example.

To avoid the edge diffraction, you'd need to stand the drivers off the wall somewhat and provide some sort of contoured surface around each driver.

But I agree that great strides are just waiting to be made in this field. Visually and practically, there's little difference btw. a flush-mounted speaker and one that protrudes even up to an inch.

I know I'd likely buy a pair for our bedroom.

Hi,

PMBuko is correct. And using a concave arrangement, like a salad bowl, would gently horn-load all the drivers. I can tell you wouldn't like the coloration that results. I mean, you could accommodate it, but if you had neutral uncolored front speakers, you'd always notice the coloration in the surrounds and it would likely become increasingly annoying over time. That's my experience in the past.

Regards,

1) Many people seem to be going for in-wall or in-ceiling speaker for the fronts and center as well, so the relative coloration is a non-factor. The builders seem to be selling this to the wives (no offense to any women here) - so any advance in this area would be an improvement.

2) You're probably giving too much credit to the potential customers that would order in-wall or in-ceiling speakers. I figure if they could hear the difference, then they would have ordered "real speakers" in the first place...

While I'm sure a market for better in-walls exists, I don't believe in-walls fit with Axiom's engineering goals. Can you imagine the look on the faces of Axiom's staffers on the day they released a speaker that predictably resulted in colored sound? I think there'd be tears all around.

The animation Peter linked to is why I mentioned adding the raised "obstacles" to the face plate. We know that the sound waves experience refraction as they pass through the opening, and that they tend to hug the surface.

What I was suggesting was to design a faceplate that uses intentional refraction (and reflection as well) to correct the "natural" refraction. Place an obstacle on the exit side wall on each side of the opening. Design that obstacle in such a way that it reflects enough of the sound back to the "proper" direction to fill in a good bit of what is lost, and also to refract (or diffuse) the remaining sound energy away in a "diluted" fashion.

Another possibility is to change the shape of the opening. Beveled in, maybe? Before they get to the exit, relfect inwards the sounds that will be bent outwards as they exit the speaker. Come up with a way to produce the sound inside of the speaker in such a way that it needs the effects of refraction from the wall to sound right. Kinda like "folding" up sound, and letting refraction "unfold" it for you.

How about putting a disk in the center of the speaker? The edges of it would refract the sound waves inward towards the center. Maybe the outward refraction of the wall plate would undo the effect and it would end up sounding right.

Just pondering...