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Listening Room Configuration and Treatment

Dialectic

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#1
My wife and I are scheduled to close on a house in the suburbs in September or October (probably October). There is a finished room in the basement that will, at least for now, be allocated to my listening hobby. The plan is to put the pair of Dutch & Dutch 8Cs in there and use them with BACCH. My hope is that in a properly configured and treated room, it will be possible to realize the full potential of BACCH and the 8Cs.

Here are the room dimensions (drawing not to scale):

room dimensions.png


Ceilings are nine feet. The little marks on each wall are small windows (two on the long wall, one on the short wall). Toward the corner diagonally opposite from the door, the floor slopes down slightly toward a steel hatch for mechanical and plumbing access (it's a finished basement). The floor has carpet, but rugs will be added to help with floor reflections. Aesthetics are a non-factor.

The desideratum of this project is to achieve results like these to the extent physically possible in a smaller room, but with a greater focus on spatial presentation of the sound via BACCH. Bass performance from the 8Cs will be fine for my needs at the outset, but I will augment them with subs in the future as D&D builds out the software in the 8Cs. The BACCH team previously has advised that, in a room with a BACCH system, treating first reflection points enhances the 3D effect of BACCH significantly.

I of course realize that I need to read Dr. Toole's book carefully to have a better theoretical grounding in this subject, but I'd be very grateful for any practical thoughts that the greatest minds in audio have on speaker placement, optimum listening positions, and room treatment products. Thank you all in advance for any responses.
 

Dialectic

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#4
I sort of think the speakers should go in front of the short wall away from the door. A lot of can be done by trial and error. The 8c's are supposed to minimize room effects by design. I am not familiar with BAACH.
Indeed, the short wall away from the door seems prima facie the best option for speaker placement, but, as the engineer and I confirmed during the inspection, the floor actually slopes down toward one corner of that wall, where the carpet somewhat crudely conceals a giant steel hatch for mechanical and plumbing access. If the speakers went along that wall, the right speaker and its stand would be on a sloping floor.

Long vs short wall, what are you thinking? How near field do you want to be?
I can sit in the near field, and BACCH reportedly works very well in the near field. However, I do not want to put the speakers on the long wall if I will have to sit exactly midway between the front and back walls, where bass may be compromised.

I am actually leaning toward putting the speakers on the short wall where the door is, putting the right speaker as close to the door as possible without allowing the door to hit it.

I will also be mounting an outside lock on the door, so there will be no concern about damage caused by children, guests et al. Not very sociable of me.
 

Soniclife

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#5
Do you want to sit in a equilateral triangle, or further back?

The short wall with doorway option will give you at most 6 feet between the speakers, in a symmetrical layout, which will put 2/3s of the room behind you in equilateral config, and a bit further back takes you to the middle of the room, which I agree is possibly problematic. Putting them on the long wall gives the opposite compromises.

Have you played with any room sims (e.g. REW)?

I'm a believer in trying all 4 options, with an open mind, and seeing if there is an obvious choice.

Is there a nice view out the windows? It would be a factor for me.
 

Dialectic

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#6
Do you want to sit in a equilateral triangle, or further back?

The short wall with doorway option will give you at most 6 feet between the speakers, in a symmetrical layout, which will put 2/3s of the room behind you in equilateral config, and a bit further back takes you to the middle of the room, which I agree is possibly problematic. Putting them on the long wall gives the opposite compromises.

Have you played with any room sims (e.g. REW)?

I'm a believer in trying all 4 options, with an open mind, and seeing if there is an obvious choice.

Is there a nice view out the windows? It would be a factor for me.
The view is nice and green, but I don't expect to do a lot of daytime listening. So, a non-factor for me.

I will play with REW tonight.
 
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#7
Firstly I make no claim to be 'one of the greatest minds in audio' (but if you insist....!). I've read Toole's Third Edition from which I learned a lot, but maybe not enough. I don't think he would like my room! No matter, I do although I'm sure it could be better.

I use this for positioning:

http://www.barrydiamentaudio.com/monitoring.htm

It works for me in a 13' x 14' x 8' high room.

With this your speakers will be about 4' from the side wall and just under 7' from the front wall. Perhaps that will avoid the slope? I'm not sure how the sound will be affected by this slope but from the speaker position point of view, if it ends up on the slope, could you not adjust it's height and angle accordingly?

I then use GIK products for room treatment - soffit traps in the wall-wall and ceiling-wall corners, and additional panels on the back and front walls, plus two panels right next to the outside of each speaker to deal with side wall reflections.

I then use EQ to tidy up, up to 200Hz. So far I haven't EQ'd any higher as I like what I'm hearing, but I plan to some time.

The sound I get is very much from speaker to speaker with a strong central image and intermediate placement if the recording has that info. I listen mostly to pop music which plays well, but the occasional orchestral and large choral pieces are only moderately satisfying.

I haven't tried BACCH but am currently reading about it as well as ambiophonics, phantom images and the rest, so perhaps I might as it looks like I have a set up that could benefit well from it.
 
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#8
I will also be mounting an outside lock on the door, so there will be no concern about damage caused by children, guests et al. Not very sociable of me.
Isn't there a danger they'll lock you in?!!!
 

Dialectic

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#10
Firstly I make no claim to be 'one of the greatest minds in audio' (but if you insist....!). I've read Toole's Third Edition from which I learned a lot, but maybe not enough. I don't think he would like my room! No matter, I do although I'm sure it could be better.

I use this for positioning:

http://www.barrydiamentaudio.com/monitoring.htm

It works for me in a 13' x 14' x 8' high room.

With this your speakers will be about 4' from the side wall and just under 7' from the front wall. Perhaps that will avoid the slope? I'm not sure how the sound will be affected by this slope but from the speaker position point of view, if it ends up on the slope, could you not adjust it's height and angle accordingly?

I then use GIK products for room treatment - soffit traps in the wall-wall and ceiling-wall corners, and additional panels on the back and front walls, plus two panels right next to the outside of each speaker to deal with side wall reflections.

I then use EQ to tidy up, up to 200Hz. So far I haven't EQ'd any higher as I like what I'm hearing, but I plan to some time.

The sound I get is very much from speaker to speaker with a strong central image and intermediate placement if the recording has that info. I listen mostly to pop music which plays well, but the occasional orchestral and large choral pieces are only moderately satisfying.

I haven't tried BACCH but am currently reading about it as well as ambiophonics, phantom images and the rest, so perhaps I might as it looks like I have a set up that could benefit well from it.
I forgot to mention that the D&D 8Cs are designed to be placed approximately 20 to 80 cm from the front wall, so I am freed of the conventional requirement to move the speakers away from the front wall.
 
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#11
Good thoughts from @Ron Texas and @Soniclife Whatever you choose, just make sure the setup is symmetrical (use a tape measure and/or laser distance measure down to 1/4" tolerance if you can). The 8c's do very well when placed almost up against whatever front wall you choose. <40cm is good, 30cm even better, as this is what they are designed for :) Unless there is a special requirement for BAACH, I would go with the equilateral triangle.

REW's room simulator is a good one and there are others like: http://www.hunecke.de/en/calculators/loudspeakers.html and https://amcoustics.com/tools/amroc

But there is no substitute for setting up and measuring the room with REW. I presume you have a measurement mic?

Aside from frequency response, REW has a plethora of views to help you better understand your room acoustics:

Waterfall view: will show you modal decay of low frequencies below the rooms transition frequency - ideally all low frequencies should decay at the same rate (but never will :). If you require bass traps, put them in the 4 corners of the room for maximum effectiveness.

Energy Time Curve (ETC): will show you the rooms early reflections for the first 40ms - rule of thumb, the reflections should be ~-15 dB down from the direct sound over that time period.

RT60 - while technically there is no reverb time in small room acoustics, REW has a good algorithm (Topt) for small rooms and this measure is useful above the rooms transition frequency to get an idea of how dead or live the room is. A nice flat response from 300Hz to 10 kHz will yield a neutral sounding room. Typical RT60 Topt ranges for small room acoustics is around 200 to 400ms. Note it is better to have a more lively room than a dead one. Most folks overdo it on the absorption rather than using diffusion. A overly absorbent room takes the life out of the music.

Those 3 basic measurements will help tune your room up. DSP, like in my sig, can shape the frequency response to a spec or taste. It may be you can get away with a few on-board PEQ filters, but like any physical room, below Schroeder is going to have it's ups and downs in frequency response.

I find https://www.atsacoustics.com/ offers quality products at an affordable price.

Once setup and system measured, share the REW .mdat and we can sort you out wrt to passive room treatments.

Good luck!
 

Thomas savage

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#12
If the drain thing is a issue you could always put a little raised shelf across to level it off and put your speakers on that .

Be a bit of buggering about to get it level but once done it's done forever. Possibly you could hide cables under it too .

Oh congratulations on the house , I'm pleased your realising your ambitions to move out of the city. :)
 

Krunok

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#13
RT60 - while technically there is no reverb time in small room acoustics, REW has a good algorithm (Topt) for small rooms and this measure is useful above the rooms transition frequency to get an idea of how dead or live the room is. A nice flat response from 300Hz to 10 kHz will yield a neutral sounding room. Typical RT60 Topt ranges for small room acoustics is around 200 to 400ms. Note it is better to have a more lively room than a dead one. Most folks overdo it on the absorption rather than using diffusion. A overly absorbent room takes the life out of the music.
As usual, very usefull hints from Mitch!

Here is RT60 response of my room (not so small, app 45m2), just as an example to what Mitch was saying (left + right speaker):


Capture.JPG


Btw, walls made of thick hollow bricks are covered with blaster panels and mineral wool in between. @Thomas savage , as you are the expert in this field, does that help? :)
 

RayDunzl

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#14
Is there a nice view out the windows? It would be a factor for me.
This remains my favorite non-multi-billionaire listening room image... Jon Iverson, Stereophile

1565803210520.png


1565803157987.png
 

Krunok

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#15
If the drain thing is a issue you could always put a little raised shelf across to level it off and put your speakers on that .

Be a bit of buggering about to get it level but once done it's done forever. Possibly you could hide cables under it too .

Oh congratulations on the house , I'm pleased your realising your ambitions to move out of the city. :)
This remains my favorite non-multi-billionaire listening room image... Jon Iverson, Stereophile

View attachment 31326

View attachment 31324
Speakers are so-so but I do like the view and the lamp! :D
 

Dialectic

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#16

RayDunzl

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#17
Last edited:

Soniclife

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#18
This remains my favorite non-multi-billionaire listening room image... Jon Iverson, Stereophile

View attachment 31326

View attachment 31324
Yeah, I could live with that.
In-laws used to have a house with a lounge with similar Windows looking down once side of a valley, and up the other, with a stream railway line at the bottom of the valley, it was full on English countryside idyll. Would have made a great listening room.
I'm also very fond of a sea view.
 

Dialectic

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#19
Is Iverson an older guy who bought his house before the tech boom? You'd probably have to be a hundred-millionaire or billionaire now to afford that place if it is located, as I suspect from the view, in the hilly area around Silicon Valley.
 

Dialectic

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#20
We will have a nice living room with a wall of windows looking back onto the nice wooded, rocky back yard, but that is where the piano will go, not the stereo.
 
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