Acoustic treatment right next to speaker... yay or nay?

N

NoD~

Audiophyte
Hello all! I have a fairly unique build, but I'll let the pictures do most of the talking.

Specifically for my install, I have in-wall, flush mounted speakers. Is there any harm in having either absorption or diffusion directly next to them, such as the picture below? My other option is to replace with drywall.

Is there a minimum distance between a speaker and treatment, if directly next to it is not ideal?
 

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TLS Guy

TLS Guy

Seriously, I have no life.
Hello all! I have a fairly unique build, but I'll let the pictures do most of the talking.

Specifically for my install, I have in-wall, flush mounted speakers. Is there any harm in having either absorption or diffusion directly next to them, such as the picture below? My other option is to replace with drywall.

Is there a minimum distance between a speaker and treatment, if directly next to it is not ideal?
My first question would be: - are those speakers designed to be flush mounted? If not, then they should not be flush mounted or they will never sound right.

The next issue is that room treatments are controversial, and good speakers should NOT require them, as it will downgrade them.

The issue with room treatments, is the room total power response. The most pleasing speakers have a wide and smooth off axis response, that closely mirrors the axis response.

Room reflections are required to make the surround natural. So in a good speaker the axis response, and the reflections, will sum to give an even smooth in room power response.

This is just one of the reasons, why you can not make a poor speaker a good one by equalization. If the axis and reflected responses are divergent to give a poor in room power response with frequency then if you equalize, then the in room response will still be divergent. For example if the axis response is good, but the off axis response poor, then the in room power response will be poor. If you try and equalize it, then you will have a poor on axis response and compound the felony.

So you can only solve these problems by careful measurement and analysis.
 
N

NoD~

Audiophyte
Thanks for the response. I have a minidsp 2x8 with a channel for each the tweet, the mid, the midbass, and the subwoofers. Each driver is fine tuned for crossover, delay, EQ, and level to give the flattest response possible at the primary listening position (using obsessive REW measurements and tweaking). So you could say these are designed to be flush mounted speaker. :)
 
TLS Guy

TLS Guy

Seriously, I have no life.
Thanks for the response. I have a minidsp 2x8 with a channel for each the tweet, the mid, the midbass, and the subwoofers. Each driver is fine tuned for crossover, delay, EQ, and level to give the flattest response possible at the primary listening position (using obsessive REW measurements and tweaking). So you could say these are designed to be flush mounted speaker. :)
Not really. If it was designed as a free standing speaker, then it will have Baffle Step Compensation, which manages the half space, full space transition frequency and below. So a flush mounted speaker only has a half room response and no transition frequency. So the crossovers require redesign for flush mounting.
 
N

NoD~

Audiophyte
Not really. If it was designed as a free standing speaker, then it will have Baffle Step Compensation, which manages the half space, full space transition frequency and below. So a flush mounted speaker only has a half room response and no transition frequency. So the crossovers require redesign for flush mounting.
There is no passive crossovers. These drivers are exclusively fully active. They were never tuned for anything but their current in-wall home. If you'd like, I can list drivers with their various t/s and response, my own readings, the current crossover and EQ settings per driver channel, amps, etc. but I think that would be better suited for another thread. (which I plan to start eventually)

My point of this thread is to simply save me time in removing the diffusers next to my front L/R custom-built channels and trying absorption or a hard surface and testing by using other user feedback. Youtube channel "AVPro Edge" has plenty of great videos on acoustics, but doesn't quite address my circumstances.
 
TLS Guy

TLS Guy

Seriously, I have no life.
There is no passive crossovers. These drivers are exclusively fully active. They were never tuned for anything but their current in-wall home. If you'd like, I can list drivers with their various t/s and response, my own readings, the current crossover and EQ settings per driver channel, amps, etc. but I think that would be better suited for another thread. (which I plan to start eventually)

My point of this thread is to simply save me time in removing the diffusers next to my front L/R custom-built channels and trying absorption or a hard surface and testing by using other user feedback. Youtube channel "AVPro Edge" has plenty of great videos on acoustics, but doesn't quite address my circumstances.
So these are DIY speakers. I also use active DIY speakers, and the front three have variable BSC, which is instrument set.







The system is driven from 18 power amp channels. All except the surrounds and ceiling speakers are transmission line design.

I have also done an in wall system, including sub which is a TL sub.



I would be interested to know more details of your system.
 
VoidX

VoidX

Audioholic Intern
Room reflections are required to make the surround natural. So in a good speaker the axis response, and the reflections, will sum to give an even smooth in room power response.
This is why THX mostly covers the front wall, and I would advise OP to continue with the work, but - in line with what you say - only on the front. Surrounds (especially for 5.1) need dispersion, which is natural in the room, but fronts need accurate panning and minimal interference. Surrounds bouncing on the front wall is also an issue, that is handled in the mix. Most professional installs, including home theatres and certified studios, completely baffle the front, while making the side walls more reflective, sometimes with a checkerboard pattern of absorbers and plain walls.
 
Trell

Trell

Audioholic Ninja
This is why THX mostly covers the front wall, and I would advise OP to continue with the work, but - in line with what you say - only on the front. Surrounds (especially for 5.1) need dispersion, which is natural in the room, but fronts need accurate panning and minimal interference. Surrounds bouncing on the front wall is also an issue, that is handled in the mix. Most professional installs, including home theatres and certified studios, completely baffle the front, while making the side walls more reflective, sometimes with a checkerboard pattern of absorbers and plain walls.
They do? A quick googling did not give me any hits supporting your claim.
 
VoidX

VoidX

Audioholic Intern
They do? A quick googling did not give me any hits supporting your claim.
Check the links, one is the largest premium HT installer company in our country, the other is the only THX certified studio around here. I've also seen IMAX do this, but not always. This is also an extensive topic in the Level 2 (integrator) THX exam, that's my main source.
 
TLS Guy

TLS Guy

Seriously, I have no life.
This is why THX mostly covers the front wall, and I would advise OP to continue with the work, but - in line with what you say - only on the front. Surrounds (especially for 5.1) need dispersion, which is natural in the room, but fronts need accurate panning and minimal interference. Surrounds bouncing on the front wall is also an issue, that is handled in the mix. Most professional installs, including home theatres and certified studios, completely baffle the front, while making the side walls more reflective, sometimes with a checkerboard pattern of absorbers and plain walls.
And that advice is dead wrong. THX are persisting in yesterday's failed theories. That old concept of dead end live end BS is a dead as a dodo among those who know what they are doing.
 
VoidX

VoidX

Audioholic Intern
That old concept of dead end live end BS is a dead as a dodo among those who know what they are doing.
Now that's something I'd like to read more about. My subjective opinion is that THX rooms sound the best by far (and those are the only one that can convey correct directions at any seat), but I'm open to trying anything else.
 
VonMagnum

VonMagnum

Senior Audioholic
The next issue is that room treatments are controversial, and good speakers should NOT require them, as it will downgrade them.
WTF do corrections/alterations for acoustics in a room got to do with the speakers? There's a reason people sing in the shower and concert halls are often designed with no parallel walls. It's called acoustics. If you don't think getting rid of things like slap echo in a room are a good thing, we clearly have nothing in common.

I like my music to sound like the recording, not the room they're played in. Now if you're using Legacy Whispers, you probably don't have to worry about the room, but you're also going to be the only listener unless you sit the person on your lap.

While I'm a fan of dipole planar speakers in a reasonably treated, but somewhat live room to give an artist is actually playing in my room feel (Carver AL-IIIs with custom active crossovers have given this to me for 26 years now with stereo playback), I also believe in dead room/dead room with multiple speaker arrays to handle simulated reflections of the original room, not my own room, which is what I'm doing now in my home theater with 17 speakers for Atmos/Auro music and it's unbelievable sounding.

The room the Carvers are in has amazing bass response. I get about +/- 3dB bass and 4dB overall response with no room treatments beyond carpeting, heavy drapes covering the window where the first sidewall reflection is and open on the other side. The non-parallel back wall and hallway seem to be what naturally controls the bass modes.

The theater room uses textured tapestries plus heavy draping along with bookcases and even the brick fireplace hearth (actual fireplace is outboard antique) to break up and absorb the sound waves and is almost perfectly controlled to sound room levels down to bass frequencies where it could still be improved a bit with traps. As dead as it sounds talking, the room lights up with 17 speaker playback, transporting me to the church on Himmelborgan and Himmelrand Auro-3D recordings rather than sounding like a church organ is in my house.
 
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