Possibly Really Dumb Question re: Placing Speakers Semi-In Wall

[SuicideSquid]

Hi guys,

I've got a set of Totem Forests as my mains, and a matching centre channel I built myself using the same drivers as the Forest, everything running through an active crossover (Dayton Audio) and room correction via Denon X4700H.

I've been considering switching to KEF in-walls to reclaim some floor space, but the cost is significant - the Forests retain their resale value pretty well but I doubt I'd get much for my matching custom centre, and aside from the significant amount of the room the Forests take up I'm very happy with how the everything sounds.

Had a thought today - what if I cut into the drywall and built boxes 3" or so into the wall (the wall is about 5" deep) to set the speakers in to reclaim a lot of the floor space, and leave a portion around the rear port open to the insulation in the wall to absorb some of the rear reflection/port noise and reduce the bass boost effect of setting them back like this.

Is that completely insane? The fronts of the speakers would still be protruding 3-4" out from the wall but that would give me almost all my floor space back (right now they're 12" off the wall, so about 20" from the rear of the wall to the front of the speaker). Am I going to cause all kinds of weird problems with edges and baffles and weird reflections/diffraction and things along with potential bass issues? Or will the issues be minor and likely fixable by tweaking the crossovers and room correction?

Feedback much appreciated - thanks!

 

[kemmler3D]

Hi guys,

I've got a set of Totem Forests as my mains, and a matching centre channel I built myself using the same drivers as the Forest, everything running through an active crossover (Dayton Audio) and room correction via Denon X4700H.

I've been considering switching to KEF in-walls to reclaim some floor space, but the cost is significant - the Forests retain their resale value pretty well but I doubt I'd get much for my matching custom centre, and aside from the significant amount of the room the Forests take up I'm very happy with how the everything sounds.

Had a thought today - what if I cut into the drywall and built boxes 3" or so into the wall (the wall is about 5" deep) to set the speakers in to reclaim a lot of the floor space, and leave a portion around the rear port open to the insulation in the wall to absorb some of the rear reflection/port noise and reduce the bass boost effect of setting them back like this.

Is that completely insane? The fronts of the speakers would still be protruding 3-4" out from the wall but that would give me almost all my floor space back (right now they're 12" off the wall, so about 20" from the rear of the wall to the front of the speaker). Am I going to cause all kinds of weird problems with edges and baffles and weird reflections/diffraction and things along with potential bass issues? Or will the issues be minor and likely fixable by tweaking the crossovers and room correction?

Feedback much appreciated - thanks!

My guess is you see an improvement in SBIR and diffraction will probably be not a big deal. As for whether it hurts or helps in room response, hard to guess in advance.

I don't think it's a crazy idea unless it makes your room look crazy.

 

[kyuu]

Wouldn't cavity resonances be an issue, @kemmler3D?

 

[kemmler3D]

Wouldn't cavity resonances be an issue, @kemmler3D?

If it were done this way, I assume they would be. But the way I read @SuicideSquid 's post, they're just looking to cut a hole in the wall and nestle the speaker inside the wall, I didn't see that there was going to be a cubby built for the speaker.

 

[SuicideSquid]

If it were done this way, I assume they would be. But the way I read @SuicideSquid 's post, they're just looking to cut a hole in the wall and nestle the speaker inside the wall, I didn't see that there was going to be a cubby built for the speaker.

Kind of halfway in between actually. Intention would be to build a bit of a cubby, but without the back wall, just leaving the back open to insulation (well, likely covering it with fabric to allow sound to pass through but preventing insulation fibres from escaping into the room, but close enough).

 

[kemmler3D]

Kind of halfway in between actually. Intention would be to build a bit of a cubby, but without the back wall, just leaving the back open to insulation (well, likely covering it with fabric to allow sound to pass through but preventing insulation fibres from escaping into the room, but close enough).

I see... depending on how much space there is to the side of the speaker then, @kyuu is right that you might get some unwanted resonances from the horizontal spaces.

 

[SuicideSquid]

I see... depending on how much space there is to the side of the speaker then, @kyuu is right that you might get some unwanted resonances from the horizontal spaces.

Better to keep it tight or give extra space to avoid this? Ideally would like to leave almost no space around the speaker. If I was just winging this I'd probably leave no more than about 1/2" on the sides, rear open, speakers also wouldn't be flush with the wall as in Kyuu's photo, but about half-in and half-out of the wall.

 

[kyuu]

Kind of halfway in between actually. Intention would be to build a bit of a cubby, but without the back wall, just leaving the back open to insulation (well, likely covering it with fabric to allow sound to pass through but preventing insulation fibres from escaping into the room, but close enough).

Behind that insulation would be wall, though, no? So it's still a little cubby hole, and you'll still get the cavity resonances. The insulation would absorb some of the high frequencies, sure, but would be ineffective against the the low frequencies where the resonances would be the worst.

The best solution here would seem to be... in-wall speakers.

 

[SuicideSquid]

The best solution here would seem to be... in-wall speakers.

 

[kemmler3D]

would be ineffective against the the low frequencies where the resonances would be the worst.

If the sides are very close to the speaker... where are we going to get low frequency resonances from? I think that if the spacing is tight, you push the resonance high, and since HF is going to be more directional, you won't expect much HF resonance in that gap at all.

Better to keep it tight or give extra space to avoid this? Ideally would like to leave almost no space around the speaker.

I think the tighter the better, with the idea of pushing the resonances higher and (hopefully) out of the range where there will be significant energy traveling into the cubby.

 

[wwenze]

Just stuff sponges, lots of it, into the cavity..........

You might want to EQ to counter the effect of baffle-step compensation since that's already built into good speakers that know they will be placed on tables and not flush in wall. Or not, some people like the bass boost.

 

[SuicideSquid]

Just stuff sponges, lots of it, into the cavity..........

You might want to EQ to counter the effect of baffle-step compensation since that's already built into good speakers that know they will be placed on tables and not flush in wall. Or not, some people like the bass boost.

Forests are floorstanding and I'm using an active crossover already so if there was baffle step compensation in the crossover it's already gone!