Standard speakers mounted through wall

[Morticae]

Title pretty much sums it up. I moved into a new house with a media room on the second story. All walls except the rear are surrounded by wide open attic space.

I have a couple of Ascend Acoustics CBM 170s that I plan to mount as my rears (sides actually, 5.1). The room is juuuuust small enough and they are juuuuust bulky enough that it will be annoying to have them sticking out their depth + mounting bracket from the wall.

So. I'm thinking about cutting a couple holes in the walls, building an in-wall "frame" with 2x4s, padding the edges, sliding the speakers in so they only stick out an inch or two, and then trimming it to look nice.

Anyone have any experience with this? Anything to look out for? Any reason (physics? pressure differentials?) that I should NOT do this? I can't think of one, but I'd like a second opinion before I cut a hole (2) in my walls.

Thanks!

 

[Morticae]

Okay I lied, I thought of one.
Moisture in the attic space. The port in the back of these babies will obviously be exposed to any humidity present in the attic, which will be similar to the outside humidity. I don't live anywhere near an ocean, but will average humidity wreck standard speakers?

 

[Exit]

I've read somewhere that free standing speakers should not be built into home theater shelving systems because it will alter the sound output negatively. I don't remember the particular reasoning for this but I think bass gets emphasized and the speakers are harder to toe in to the listening position. I would think building them in the wall would be the same or worse than building them into a shelving system. Maybe someone else can recall reading about this subject and provide a link.

 

[Morticae]

Thanks for the response. I know that having rear-ported speakers within a few inches of an obstruction will affect the sound. Is this what you're referring to with the shelving maybe?

As far as I know, no (desirable) sound should be emitted from the port. Is something else at work here?

 

[Exit]

The only reason I know of for a port is that it is for a bass reflex design where the sound off the back of the speaker is tuned by the port to reinforce the bass output from the front of the speaker. Turn them on and play some music with strong low bass. Put your ear next to the port and see if bass is coming out or not - then you will know. If it is the bass port of a bass reflex speaker design, then you definitely do not want to enclose the speaker and cut off that bass port reinforcement.

Putting a freestanding speaker in an enclosed situation alters the sound. Bass output which normally spreads in all directions (360 degrees) is more focused in an 180 degree frontal area when enclosed. This can alter the bass/mid/treble tone balance designed by the manufacturer. I am pretty sure this is close to what I read but I still hope someone else can link to a writeup on this.

 

[TLS Guy]

There is indeed output from the port. Almost all the low bass output comes from the port. Typically for speakers like yours almost all the output from around 70 to 40 Hz will be from the port. That is reason enough for not carrying out your plan. Also the speaker is likely voiced to be away from the room boundary. However if the speaker is bass shy and didn't have a rear port it might improve it.