Hey folks,
Just starting out on my diy speaker foray and am aiming for a 7.1 home theater build eventually.
I'm intending to do Overnight Sensations LCR, and probably MTM all round. But the problem is while my rear surrounds I can happily wall mount in the corners of my room the left and rights will need to be in-wall.
Has anyone made an in-wall OS build?
Or would anyone be able to recommend a commercial in-wall option that might have reasonable voice matching to the OS MTM I'll have for the other speakers?
Thanks
--
Ben
Just starting out on my diy speaker foray and am aiming for a 7.1 home theater build eventually.
I'm intending to do Overnight Sensations LCR, and probably MTM all round. But the problem is while my rear surrounds I can happily wall mount in the corners of my room the left and rights will need to be in-wall.
Has anyone made an in-wall OS build?
Or would anyone be able to recommend a commercial in-wall option that might have reasonable voice matching to the OS MTM I'll have for the other speakers?
Thanks
--
Ben
To add some detail I have a fairly small room 15ft deep and a little over 10ft wide hence the in-walls needed for the side speakers and trying to go for small speaker designs overall.
The depth of wall is unfortunately a standard 2x4 stud so 3.5" max between 16" studs and enclosed with drywall. Definitely tight.
I am fairly handy though and have access to 3d printing and CNC machinery. Also have electronics and CAD experience so am not daunted by going off the beaten path here, but crucially I lack all speaker design knowledge so any advice here would be appreciated.
The depth of wall is unfortunately a standard 2x4 stud so 3.5" max between 16" studs and enclosed with drywall. Definitely tight.
I am fairly handy though and have access to 3d printing and CNC machinery. Also have electronics and CAD experience so am not daunted by going off the beaten path here, but crucially I lack all speaker design knowledge so any advice here would be appreciated.
Your on-wall and in-wall versions should have similar frequency response variations compared to the original based on boundary reinforcement. If your home theater receiver/processor has automatic equalization, it should be able to compensate for that whole issue. If it doesn't, they'll still have similar sound all the way around, so if you don't have perfectionist expectations, you'll probably be happy with both versions.
Again assuming non-perfection goals, I'd suggest just jiggling the dimensions of the enclosure to fit in your wall so your shallow cabinet has the same internal volume as the original. You may need to get creative with the ports.
I'm glossing over some of the other changes that happen when you do something like this, because they tend to be smaller effects and not those that will bother an average listener. If you want to go down that rabbit hole, there are plenty of opinions on those subjects that will freely flow if you want them.
Again assuming non-perfection goals, I'd suggest just jiggling the dimensions of the enclosure to fit in your wall so your shallow cabinet has the same internal volume as the original. You may need to get creative with the ports.
I'm glossing over some of the other changes that happen when you do something like this, because they tend to be smaller effects and not those that will bother an average listener. If you want to go down that rabbit hole, there are plenty of opinions on those subjects that will freely flow if you want them.
Haha yes I've done enough reading on the forums to see the depth you can go to here but yeah definitely not aiming at perfection, just 'good'.
So if I understand correctly I could do something like these but mount them inside the wall instead?
https://forums.audioholics.com/foru...-sensation-for-surround-and-atmos-use.106191/
They're a little deeper than will fit in my wall, not sure on the WAF of a small stickout so may need to further widen/heighten the back of the box to make up for the volume at an even shallower depth, but I can probably make that work.
So if I understand correctly I could do something like these but mount them inside the wall instead?
https://forums.audioholics.com/foru...-sensation-for-surround-and-atmos-use.106191/
They're a little deeper than will fit in my wall, not sure on the WAF of a small stickout so may need to further widen/heighten the back of the box to make up for the volume at an even shallower depth, but I can probably make that work.
That's the idea.
The HiVi B4N is a little under 3 inches total depth, so I think you can make it work. You might have to rout out a small pocket to clear the magnet, use a thin front/back wall for the enclosure with a bunch of bracing, or use some 1/4 inch drywall to get some extra depth, etc. A lot of it will come down to all the details in your wall and how you prefer to build things.
Another approach would be to just use the wall cavity as an infinite baffle, and omit the enclosure. The low frequency roll-off will start at a higher frequency if you do that, but with a subwoofer it would probably be OK. Again, some of this comes down to what you really want to build and what kind of tuning options you have in your processor.
If you proceed with the project, let us know how it goes. And if you want more input, keep asking questions.
The HiVi B4N is a little under 3 inches total depth, so I think you can make it work. You might have to rout out a small pocket to clear the magnet, use a thin front/back wall for the enclosure with a bunch of bracing, or use some 1/4 inch drywall to get some extra depth, etc. A lot of it will come down to all the details in your wall and how you prefer to build things.
Another approach would be to just use the wall cavity as an infinite baffle, and omit the enclosure. The low frequency roll-off will start at a higher frequency if you do that, but with a subwoofer it would probably be OK. Again, some of this comes down to what you really want to build and what kind of tuning options you have in your processor.
If you proceed with the project, let us know how it goes. And if you want more input, keep asking questions.
Yes I was just reading about infinite baffle approach. Tbh given these are left and right surrounds in a likely 7.2.4 setup eventually, with two small subs either side of the sofa listening area the LF roll-off should be fine with the subs picking up the slack in exactly the right place?
Certainly a lot easier to take that approach as the hole size in the wall might be prohibitive to fit such a large enclosure into it and I'd rather not redo all the drywall.
Thinking I could make the regular MTM front baffle with some 3d printed bracket to hold the crossover off the bottom of the baffle where it would usually live and then mount the baffle into the hole using a frame clamp if I can find an appropriate sized one or just 3d print or cnc one of those too.
My guess is these drivers aren't big or powerful enough to cause too much resonance on the drywall? Would this approach benefit from stuffing the cavity or padding the rear drywall?
I haven't yet picked out a receiver, I'm abandoning my 10 year old Yamaha soundbar as we move into our new property so am quite looking forward to this venture into speaker building! So open to suggestions on good receivers for a 7.2.4 setup such as this too.
Certainly a lot easier to take that approach as the hole size in the wall might be prohibitive to fit such a large enclosure into it and I'd rather not redo all the drywall.
Thinking I could make the regular MTM front baffle with some 3d printed bracket to hold the crossover off the bottom of the baffle where it would usually live and then mount the baffle into the hole using a frame clamp if I can find an appropriate sized one or just 3d print or cnc one of those too.
My guess is these drivers aren't big or powerful enough to cause too much resonance on the drywall? Would this approach benefit from stuffing the cavity or padding the rear drywall?
I haven't yet picked out a receiver, I'm abandoning my 10 year old Yamaha soundbar as we move into our new property so am quite looking forward to this venture into speaker building! So open to suggestions on good receivers for a 7.2.4 setup such as this too.
Sorry, the logic doesn't support this. Smaller output, less resonant energy, same ratio.
Not sure I understand Allen, would you know of any good resources to read on that topic?
As I currently understand it my options are:
1. Build a somewhat compromised in wall setup with the regular OS MTM drivers and crossover but without an enclosure and live with some less than perfect response and hope to make it up via the receiver adjustment and subs.
2. Build a larger shallow enclosure and embed it into the wall somehow (likely requiring more drywall work) and hope for a more consistent result with the other speakers this way.
3. Pick a commercial in wall speaker that is roughly equivalent to the OS MTM. Don't yet know of any that use similar drivers so not sure this is viable yet.
I'm thinking I'll try 1, worst case I end up with drivers I need to build an enclosure for and make a larger hole in the wall!
As I currently understand it my options are:
1. Build a somewhat compromised in wall setup with the regular OS MTM drivers and crossover but without an enclosure and live with some less than perfect response and hope to make it up via the receiver adjustment and subs.
2. Build a larger shallow enclosure and embed it into the wall somehow (likely requiring more drywall work) and hope for a more consistent result with the other speakers this way.
3. Pick a commercial in wall speaker that is roughly equivalent to the OS MTM. Don't yet know of any that use similar drivers so not sure this is viable yet.
I'm thinking I'll try 1, worst case I end up with drivers I need to build an enclosure for and make a larger hole in the wall!
Drywall on standard stud spacing is pretty lively. Many in-walls do mount to drywall, but you may want to have your baffle mount to more solid structure. Or mount the baffle close to a stud where things are stiffer. You could add bracing/structure if you decide the sound is suffering from its lack.
Some acoustic foam in the general vicinity of the woofers would be a good idea. The thicker the better (but leave some breathing room around the woofers). This is about absorbing sound that's reflecting off the drywall/studs though, not about trying to damp vibration. Those are two separate things that normally require different approaches.
I typically only use 3D printed parts for things where it provides a significant benefit (complicated geometry or difficult thicknesses). You can often make something stronger and more inert with pedestrian materials if the shapes are simple.
I'm just saying that resonance normally operates independent of level. You don't need to get to a certain level to 'set it off'.. it's always there.
"Drywall on standard stud spacing is pretty lively." - 200% right
In-wall speakers are much trickier than it seems. My drywall oscillates around 200Hz. You can check yours by measuring wall reflections. You can't mount anything vibrating on drywall without creating a distributed mode radiator which will be horribly non-linear. You must vibro-isolate the spk enclosure from the drywall and stud structure through an amortization system with f < fs/10. A friend of mine used to install closed-box in-wall systems and he charged ~2x for his work above the cost of premium speakers he installed.
But as a hobby - your idea it's wonderful! You'll learn a lot in the next few years.
In-wall speakers are much trickier than it seems. My drywall oscillates around 200Hz. You can check yours by measuring wall reflections. You can't mount anything vibrating on drywall without creating a distributed mode radiator which will be horribly non-linear. You must vibro-isolate the spk enclosure from the drywall and stud structure through an amortization system with f < fs/10. A friend of mine used to install closed-box in-wall systems and he charged ~2x for his work above the cost of premium speakers he installed.
But as a hobby - your idea it's wonderful! You'll learn a lot in the next few years.
Any wall that (eventually) becomes the baffle must be rigid and free of resonances (use enough bracing & padding). That is, this wall needs to be strong enough to 'house' both speakers and subs at full power. Concrete walls are rigid enough but drywall (or plaster wall) is probably too weak to satisfy this.
https://acousticfrontiers.com/blogs/articles/thx-baffle-walls-design-build-and-benefits
I remember having seen details of (THX certified) baffle walls with pictures etc. somewhere, but am unfortunately unable to recollect where that was. If you're lucky you might even find some drawings of baffle-wall reinforcements, by just looking around (Google).
https://acousticfrontiers.com/blogs/articles/thx-baffle-walls-design-build-and-benefits
I remember having seen details of (THX certified) baffle walls with pictures etc. somewhere, but am unfortunately unable to recollect where that was. If you're lucky you might even find some drawings of baffle-wall reinforcements, by just looking around (Google).
Gotcha.
I think given I can't completely replace this wall my best bet will be to insert and toenail screw 2x4 framing inside the cavity to make an air space that's appropriate for the drivers and screw+glue that framing to the existing drywall as best I can. It'll be fiddly and messy without taking the drywall out completely but I think manageable.
That should add some rigidity to the drywall as well as provide the right volume of air for the drivers. I can also seal around the inside of that cavity while I'm at it and put stuffing into the other parts of the boxed off area above/below the speaker cavity to try and further deaden the space. Maybe add some dynamat to the front and back drywall areas while I'm at it?
This should also give me something rigid to screw the 1/2" mdf baffle to, and if I 45degree chamfer the edges of that baffle then hopefully it all won't look ot sound too bad? That then solves mounting problem too.
Seems like a plan, will report back when I get around to actually doing this in a few months time!
I think given I can't completely replace this wall my best bet will be to insert and toenail screw 2x4 framing inside the cavity to make an air space that's appropriate for the drivers and screw+glue that framing to the existing drywall as best I can. It'll be fiddly and messy without taking the drywall out completely but I think manageable.
That should add some rigidity to the drywall as well as provide the right volume of air for the drivers. I can also seal around the inside of that cavity while I'm at it and put stuffing into the other parts of the boxed off area above/below the speaker cavity to try and further deaden the space. Maybe add some dynamat to the front and back drywall areas while I'm at it?
This should also give me something rigid to screw the 1/2" mdf baffle to, and if I 45degree chamfer the edges of that baffle then hopefully it all won't look ot sound too bad? That then solves mounting problem too.
Seems like a plan, will report back when I get around to actually doing this in a few months time!