What is the right approach for room treatment in high end audio ?

[tuff]

Hi,

I am certainly not the "like people whohave a lot of experience" to add here but since the topic interests me and I am fighting my room, I'll chip in.

My room is horrid (there is a little drawing i put in another thread). Concrete and tile and glass. I have no space behind me. And I have an asymmetrical placement where there is a lot of space to the left and far lesser on the right. And I have a 55" sheet of glass between my speakers. I might as well as shoot myself in the face after signing an organ donor form you'd think. Kit wise decent and entertaining but nothing to talk about.

Actually it is not that bad, really.

Positioning, I like the audio beat method. I have a nice tight phantom centre. I have a decent stereo image. TBH I'm talking 1.3mp Nokia E63 type relative to the IMAX3D that I read about on HFV and elsewhere.

I started stupid and put in BBA - cloud, side back and front - before getting a mic. and there is nothing I can do about it now - without calling in a painting crew and that is not worth the scorn snigger and derision I will get from the SO. Not to speak of the bother and expense.

I have DRC. It works. for me. No sub needed, no thank you. It also tightens up the image a shade.

Someday I'll get diffusion instead of absorption on the side - I'd like a little more shimmer and shine. Bass is nice and tuneful. Pianos and voices sound good.

From my experiments and bumbling I a) cannot see the point of untreated rooms and would much rather stick a knitting needle into my ear or travel by a share auto with a boom box b) know that someday I'll figure it out a little better and hopefully get some more out of my rig c) wish I had the money to buy a shack with a purpose built listening room ;P

ciao
gr

I laughed hard after reading this....Thanks for keeping it real.

 

[square_wave]

I am thinking about all this in this way.

All, things in your room will have the following properties. It does not matter if it is designed and sold as an acoustic treatment product or not. Sofas, curtains, bookshelf loaded with material, plants etc.

1. Absorption
2. Diffusion
3. Some bass trapping capability.

So, technically speaking, while furnishing your listening room, you are actually treating your room although it is done in a random manner.

1. For example, can you choose a sofa which has certain acoustic properties ?
2. What about the curtains or carpets that you choose ?
3. Is there a way to design bookshelves which have good diffusion properties ?
4. Are hard walls better ? Are wooden walls better ? Is it better to leave the side walls non plastered ?
5. What is the right material ( custom or furnishing based ), to take care of the reflections you see in the pic below ?

Are there some critical things that one must take care that are universally agreed upon ?

While thinking about this, I am sure there are exceptional situations where people might take custom decisions because they have rooms or setups which need such special approaches. Let’s exclude such situations. Let’s think about the normal adequate size rectangular listening room where you are not listening in a nearfield manner.

 

[Hari Iyer]

I have confined to just use some absorption in the first reflection point. Since i have gone full-range couple of months ago, i dont have too much bass to worry about. Its just fine enough for my room.

 

[prem]

square_wave, your diagram is only showing first reflection points. Most of these can be addressed by wall hangings, curtains, book shelf with randomly placed books of different sizes, plants, carpet/rugs, etc. Always use natural material like cotton, jute, wool, silk, etc for curtains, carpets and wall hangings. No synthetic stuff here. If you are using wood panels, leave some distance between wall and panel so that some bass absorption takes place. Make sure the panel is rigidly connected to the wall. Else it will resonate. If you hear a woody resonance drill a 2 mm hole in the panel so that air escapes and it becomes less resonant.

The biggger problem is bass at the four corners of the room. Accurate speaker placement can reduce the bass issues but if they are still not resolved, first try simple things like chairs, stools, etc to break up the standing waves at the corners. If that also doesn’t solve the problem, you may have to look at bass traps. IME, I like tube traps better than panel traps.

If you want to do this whole thing very scientifically, then get a professional. He will then take measurements and recommend/build stuff to specifically solve those issues. It’s not a job for an amateur. You can go very wrong. Hope this helps

 

[prem]

On a separate note, do a very simple exercise. Get a drummer, guitar player and a vocalist to your place. Ask them to perform something. If you find it good sounding, then your room is reasonably fine. In that case all you need to do is work on speaker placement

Also a studio treatment is very different because there they want to kill every reflection since they want to hear deep into the music to enable them to master better. In normal listening, some reflections add to the reverberant field and make it more natural sounding.

 

[arj]

For a Sofa, as mentioned by Prem get a fabric sofa but with solid wood inside. eg I have a couch which has a board inside which resonates and that changes the vocal signature !
For the bookshelf, just fill it with books

 

[vivek_r]

Can the topic be changed to what's the right approach with/without divorce option please?

I know I have a horribly live room (kid has asthma, carpets/heavy furnishings are anathema), so the only thing I can do is hear through the room or lech at DIY forums (towels, cork are latest obsession)...but still enjoy the music thankfully and can listen through the sound...the flip side is that I will never realise the potential of my system (and that's probably why I shouldn't spend more?).

Sidvee raised an important point - measurement! Otherwise, its some real and some imagined problems with expert opinions coming left and right (stereophonic!).


Vivek

 

[prem]

Vivek_r, there’s only one right way. Take measurements and get a professional to set the room right. All others are non scientific but do help in reducing room issues. It’s for you to decide which route to take. I have done both. As I had mentioned earlier for high efficiency speakers with low power amps, I never felt the need for professional help.

 

[Nikhil]

Are there any good professional room treatment specialists here in India?

I remember meeting one company from Mumbai at the Bangalore show some years ago who were very capable. However they were from the pro studio supply side of the business and I am not sure if they provided consultancy in room treatment for home audio / home theater applications.


.

 

[sdurani]

Are there some critical things that one must take care that are universally agreed upon ?

Harman had done research into room correction that resulted in a couple of generalities about listener preference.

First, the smoother the frequency response, the more the overall sound was preferred. This doesn't mean a flat response (horizontal line), just a smooth response (minimized peaks & dips).

Second, when it came to frequency response, perceptually flat was preferred to measured flat. Our human hearing is not equally sensitive at all frequencies. In fact, we are a lot less sensitive to bass. So boosting low frequencies gives the perception of all frequencies being the same level (we think it's flat, even though it doesn't measure that way).

Haven't heard any disagreement against either point. They seem to be universally agreed upon. Use whatever combination of placement, treatment and equalization to get there.

 

[square_wave]

If I were to list key points as a guideline,

1. Measuring and fixing bumps and dips in the frequency responses. Use both measurements as well as listening to solve this. Perception is key.
2. Eliminate slap echo as much as possible
3. Try and get the room as close to the golden ratio as possible
4. Speaker positioning ( this can solve a lot of issues )
5. Treat first reflection points with diffusers and absorbers to get the right balance of live and damping properties in the room. This can be achieved by professionally created panels ( Rpg is a good example ) or rugs, bookshelves with books etc.

 

[unleash_me]

Carpets, curtains, sofa, chairs, bookshelves with books in it, material of the walls / floor / ceiling. Everything changes the sound in someway...

I do a combination of all the above; strictly keeping WAF an utmost priority!

Inspired by an article online, I recently got a couple of these Ikea shades and 'strategically' added them to the living room – actually a separate room, not a 'hall' like most homes. The hue lights keep the family happy. Did it help with the acoustics? I would say, yes. But to what extent? I'm not sure, objectively.

 

[renjith lal]

Hi,
I have one question regarding acoustic treatment . For a near wall listening position in a living room placing acoustic panels behind the speakers
or behind the listening position which one will give better performance? My question is front wall or rear wall treatment which one will be a better option for a near wall listening position.

 

[sdurani]

I have one question regarding acoustic treatment . For a near wall listening position in a living room placing acoustic panels behind the speakers or behind the listening position which one will give better performance?

IF you can only do one of those, then behind & between the speakers will be more helpful because it will reduce boundary interference (that can cause dips in the frequency response) and minimize reflections in general off the front wall (that can muddy the front soundstage).

If you can do more treatments, then the second place I would put them is the middle of the back wall. Third place would be contralateral reflections on the side walls.

 

[renjith lal]

IF you can only do one of those, then behind & between the speakers will be more helpful because it will reduce boundary interference (that can cause dips in the frequency response) and minimize reflections in general off the front wall (that can muddy the front soundstage).

If you can do more treatments, then the second place I would put them is the middle of the back wall. Third place would be contralateral reflections on the side walls.

Treating behind the speakers (front wall) give more benefit than behind the seating position?
In my case I have a 55 inch TV in between speakers. So treating means just behind the speakers?

Second is behind mid of back wall and third side reflections. Thanks for the reply.

 

[jls001]

Are there any good professional room treatment specialists here in India?

I remember meeting one company from Mumbai at the Bangalore show some years ago who were very capable. However they were from the pro studio supply side of the business and I am not sure if they provided consultancy in room treatment for home audio / home theater applications.
.

The few pro guys I've come across tend to treat a home audio room like they would a recording studio, meaning they would over dampen and kill the sound either partially and sometimes even completely, leaving no trace of liveliness in music playback.

I agree with an earlier post on this thread by sdurani that room treatment must be a judicious mix of bass trapping, absorption, and diffusion. The operative word here is judicious.

 

[sdurani]

Treating behind the speakers (front wall) give more benefit than behind the seating position?

Even in this day and age of surround sound, the front soundstage remains critical: that's where your attention will be focused, whether watching a movie or listening to music. As such, it is important that the front soundstage be as clear and articulate as possible. Minimizing reflections from the front wall keeps them from muddying the sound from your front speakers.

In my case I have a 55 inch TV in between speakers. So treating means just behind the speakers?

Yes, to whatever extent you can, even around the TV. Also, if you can have someone move a hand mirror around the front wall, mark the spots where you see the reflection of your surround speakers and place absorption there.

Second is behind mid of back wall and third side reflections.

Only contralateral reflections on the side walls: i.e., left speaker reflections off the right wall and vice versa. This way, sounds intended for one side of the soundstage don't also come at you from the opposite direction.

 

[renjith lal]

Even in this day and age of surround sound, the front soundstage remains critical: that's where your attention will be focused, whether watching a movie or listening to music. As such, it is important that the front soundstage be as clear and articulate as possible. Minimizing reflections from the front wall keeps them from muddying the sound from your front speakers. Yes, to whatever extent you can, even around the TV. Also, if you can have someone move a hand mirror around the front wall, mark the spots where you see the reflection of your surround speakers and place absorption there. Only contralateral reflections on the side walls: i.e., left speaker reflections off the right wall and vice versa. This way, sounds intended for one side of the soundstage don't also come at you from the opposite direction.

Thank you very much. I have only two front (left and right) speakers and I use the same for stereo and movies. I do have an AVR but I am in an apartment and not adding more speakers now, may be later add subs. I know that front left, right and center are the most important speakers.
Strange thing when I asked a famous room treatment company they advised to treat rear wall or behind listening area than front wall or behind front speakers. Not sure they got confused with my definition of front or rear wall.

 

[sdurani]

Not sure they got confused with my definition of front or rear wall.

2-channel people often use the term "rear wall" to mean the wall behind the speakers, not behind the listener.

 

[renjith lal]

2-channel people often use the term "rear wall" to mean the wall behind the speakers, not behind the listener.

Thanks for the clarification. I will treat the front wall with absorbing panels and will add bass traps if possible.
I used to get confused always .Thanks for giving clarity on convention.