Room Treatments in the Real World

[FrantzM]

Hi

I use to be very certain about Room Treatments. It was a clear sign of a serious audiophile to have a pair of "Bass Traps" in the front corner, some RGP diffusors between the front speakers and if you really were a Big Time audiophile, a mixture of several of these contraptions along the side and back wall ... all that placed by ears and wallet thickness (They were/are rather expensive and you bought these when you could ...) ... I even tried to "treat" my room with a Forrest of Bass Traps. Then I was a subjectivist and didn't measure..

Of course results were all over the place.. Room would sound dead and/or midbass suffered, by moving the bass traps you could get some subjectively different if not better results, you lived with these and applied some rules of the day of speaker positioning. and/or you changed your amps , your cables and sometimes speakers and you might be happy .. for a while ... until it was the DAC you needed to change or to use a different preamplifier or TT or TT arm or cartridge or phono stage or ...
Then came ASR, then came Science in my audiophile life, then came research and reading. I built on that a relatively inexpensive HT system HT in a Living Room. The results are satisfying in HT mode, passable in music... I am aware of the aural limitations of this system and this room: I have a slew of headphones to let me know that... I have been for the past many years trying to build an audiophile room and a better HT room. and ....in that process managed to be even more confused about Room Treatments... Witnessing what can be achieved in the bass with multiple subs (Please do not fool yourself in thinking that, setting up and integrating multiple subs is a quick process. No! It takes weeks and the learning curve is very steep but the results are worth it) , I am at the point of questioning if one needs to treat one's room for the low bass. A gigantic (pun intended, task: Room Treatment in the bass are usually huge contraptions but what about the rest of the spectrum? Is it speaker dependent? Luminaries do not share the same opinion about Room treatments some such as Earl Geddes or Siegfried Linkwitz are not too keen on room treatments... Not sure about F. Toole , I first read about "First Reflections" in the The Absolute Sound (!!) when he helped HP tamed some of his room's problems...
When I knew less I was so sure ... now ... It has become very confusing to me.

Asking those questions: (There could be more ).

• Do we need Room Treatments?
• If Yes? How do we treat a room? With what?
• How feasible is this in a Real World of shared purpose rooms?
• What are the hallmarks of a good room? How do we measure that?
• Can I make of my listening room (Living place) a decent room for music? HT? music & HT?
• What about DRC in the context of a "treated" room?
• Can DRC replace room treatments?

So many questions... I am sure I am not alone in asking those.

Waiting for answers , replies a vigorous discussion from the collective!

Happy New Year! People!!

 

[q3cpma]

Do we need Room Treatments?

I'd say that most people with a full range system do. Especially when you consider the amount of money involved into the material, you'd want it to perform at it best.

If Yes? How do we treat a room? With what?

From my understanding, pressure based bass absorbers are almost always a scam compared to velocity ones (mineral wool panels with a wall gap).

What are the hallmarks of a good room? How do we measure that?

Ideally, it should sound exactly like the room the recording you're listening to was produced in. Since this is basically impossible, I guess fighting obvious time and frequency domain abherrations is what we should aim for.
The flattest frequency response and a cumulative spectral decay as clean (constant) as possible, basically.

Can DRC replace room treatments?

My understanding is that you can't treat cancellation/amplification of the LF waves at every listening point in the room. Same way you can't use EQ to flatten a directivity mismatch in a speaker.
And that DRC doesn't make time domain issues go away; which some frequency domain obsessed people like to ignore.

 

[dshreter]

Room treatment is such a tricky topic, because it doesn’t work in absolutes. Most equipment you shop for you’re looking for maxima, such as deepest bass response, lowest noise, most watts, etc., for the price you’re willing to pay. Room treatment is different, and people have a preference for spaces and setups that include some reflected energy - but there’s the big question of how much and from which direction.

The option exists to listen in the near field, which does let you listen to a preponderance of direct vs reflected sound. It’s not fully equivalent, but if you like the sound of near field listening, I believe you most likely would enjoy the sound of a highly treated room.

I also know that an empty and completely untreated room with typical flooring like hardwoods sounds terrible. It can be hard to even hold a conversation in a room like this, no less maximize the performance of a stereo system. To me this establishes as a rule that treatment is necessary to optimize a room. It’s arbitrary and ridiculous to think that a rug, sofa, and some art would constitute the ideal room treatment.

So now we are left with the questions of what we are trying to achieve and what treatments will achieve this? Well we have already established we don’t want the room to be too live, because a raw room sounds terrible. That points towards broadband absorption. There are varying opinions, but most point towards treating first reflections points first, and that back wall reflections are rarely a positive thing. But broadband absorption isn’t really that broad, and doesn’t handle low frequencies as well as mid to high.

So we have to look at how to treat for bass response. My take is that in typical home listening environments, bass treatment becomes fairly impractical except for highly dedicated and “ugly” spaces. For the home I do think EQ, DRC, and multiple subs are a better starting point and potentially the right finishing point in the home to deal with low bass response vs bass traps.

In the end, the space will have compromises no matter what. There’s more research needed into what compromises can be made with the least impact to subjective performance, which actually makes room treatment perhaps the most fun part of the hobby right now. There’s room for exploration and personal preference vs a rote recipe that has already been crystallized into forum group think.

 

[Hipper]

People have written books on this subject and that is where you should look. The obvious one is Floyd Toole's 'Sound Reproduction Third Edition'. Ethan Winer's book 'Audio Expert' offers a slightly different perspective. Both post on here ocassionaly.

The key question is 'how do I get my room and speakers combined to sound their best?' The answer depends on whether you have a dedicated listening room or a multi purpose one (such as a living room), and also if you listen alone or with others. If you have stereo music and multi channel home theatre that too will affect things.

A good sounding room for one person will have a smooth on axis (sound that comes straight from the speakers to your ears) frequency response with reasonably low decay times. For more then one listener you additionally need a smooth off axis (how the sound disperses side ways from the speakers) frequency response. This is partly speaker dependent so you need ones with these characteristics.

The biggest difficulty in attaining this is usually found in the bass region because bass frequency behaviour is very much dependent on the location of the speakers and your listening chair (ears) and room size and shape. Once bass has been improved the mids and highs can also be heard better. These mids and highs can be reflected off walls, floors, ceilings and objects and so can muddy the sound. My experience leads me to absorb them as best as possible. Others think these reflections, especially from the side walls, enhance the sound.

Bass can be controlled by bass traps (usually big and ugly, especially in small rooms), up to four subs (so I've read), and perhaps Digital Signal Processing (DSP). I'm not convinced that DSP can fully replace bass traps but they can help a lot. The mids and highs can be controlled by absorbers, diffusors but not so well with DSP.

In my dedicated stereo only listening room where I'm the only one that listens, I first position the speakers and chair for best bass response. Then I employ bass traps and other absorbers, then I use careful EQ to finish the job. In all this I use Room EQ Wizard (REW) to measure what is going on, both frequency response and decay times.

I think Floyd Toole describes in his book his living room/stereo/home theatre room where he employs subs and DSP but no room treatment.

Here's a couple of sites that have lots of info and videos. Real Traps is Ethan Winer:

https://realtraps.com/

https://gikacoustics.co.uk/

On this site, place in your room measurements and it will give you some idea of the problems you may face:

https://amcoustics.com/tools/amroc

 

[mkawa]

I have had long conversations with the designer of my loudspeaker system and their conclusion is that it is audiophile snake oil. Without an accurate measurement device, how the heck are you supposed to tell where to put them, what kind to buy, etc. if you want an anechoic chamber, build an actual anechoic chamber. Otherwise, focus on your loudspeaker sweet spot or buy an omnidirectional or related dsp driven design that works around a challenging room.

 

[dshreter]

I have had long conversations with the designer of my loudspeaker system and their conclusion is that it is audiophile snake oil. Without an accurate measurement device, how the heck are you supposed to tell where to put them, what kind to buy, etc. if you want an anechoic chamber, build an actual anechoic chamber. Otherwise, focus on your loudspeaker sweet spot or buy an omnidirectional or related dsp driven design that works around a challenging room.

With due respect, speaker manufacturers have a bias in that they are building a product that will be deployed primarily into untreated rooms. So they are selling a product with the promise it will sound good in those rooms, and perhaps even be designed specifically with that in mind.

The idea that room response is snake oil is absurd, and both subjective listening and measurement back this up. A room with treatment sounds obviously different (your call to make whether it sounds better), so I can’t see how it would be lumped in with snake oil products that have infected this industry.

 

[pozz]

From my understanding, pressure based bass absorbers are almost always a scam compared to velocity ones (mineral wool panels with a wall gap).

Not sure what you mean. There are plenty of highly-overpriced room treatment products, sure, but pressure-based bass absorbers (membrane traps, for example) are as useful as any other product. I think you may be hinting at the fact that true low bass control can only be achieved through specialized room design and builds from the ground up, not "bass traps" which promise absorption down to 20Hz or whatever if you throw them a corner.

I'd agree with pretty much everything else you wrote.

One thing to keep in mind for anyone reading this tread is that room treatment designs evolved specifically for control rooms in studios. I'd caution anyone interested in room treatment to not spend money too fast or too soon. It is much easier to understand the predicament you're in if you take a few measurements and post a few pictures of your living area. More often than not you're restricted to just that layout, so whatever you buy has to be maximally effective and address specific issues. Don't worry about "overdamping" your room or whatever—that would take a room full of traps. Most of the time all it takes is slightly rearranging your speakers or furniture.

A few key targeted broadband absorbers always help. There are plenty of decorative ones if that's your thing.

I have had long conversations with the designer of my loudspeaker system and their conclusion is that it is audiophile snake oil. Without an accurate measurement device, how the heck are you supposed to tell where to put them, what kind to buy, etc. if you want an anechoic chamber, build an actual anechoic chamber. Otherwise, focus on your loudspeaker sweet spot or buy an omnidirectional or related dsp driven design that works around a challenging room.

There are room treatment companies that take advantage of people. But the way you get to know what to buy and what it will affect is measurement and some acoustical knowledge, as is done here with electronics, analyzers and research.

 

[mkawa]

i should clarify that the designer (quite reasonably) thought that proven methods of dampening were great if you had the ability to measure AB response at your listening position or if you went whole hog on an anechoic chamber (it is possible to build one into a listening room with drop ceilings and so on). the designer was going to sell me the same system regardless, so this wasn't an upsell. i just asked for their opinion.

the basic idea was that i couldn't just toss some dampening material from mcmaster-carr onto problematic walls and expect a clear improvement.

 

[pozz]

i should clarify that the designer (quite reasonably) thought that proven methods of dampening were great if you had the ability to measure AB response at your listening position or if you went whole hog on an anechoic chamber (it is possible to build one into a listening room with drop ceilings and so on). the designer was going to sell me the same system regardless, so this wasn't an upsell. i just asked for their opinion.

the basic idea was that i couldn't just toss some dampening material from mcmaster-carr onto problematic walls and expect a clear improvement.

Sure, although I'd say that room treatment addresses large, difficult problems which aren't obvious to the ear. It belongs to the realm of calculation and measurement rather than blind testing. The impossiblity of doing meaningful A/B tests and the unreliability of simulation is part of the reason why these products tend to be so misapplied. Toole doesn't give too much space to the mechanics of room treatments in his book, but does note that the effects of any treatment are complex and not for the average consumer to mess with. If I were to put his opinion down to a single piece of advice, it's that it's important to invest in well-designed loudspeakers as the first order of business. A lot of the other stuff that follows is, well, just stuff.

 

[Darkweb]

1. Add some soft materials to your room if it’s filled with hard surfaces. Don’t over-do it, err to “live” side rather than dead. Most carpeted rooms with soft furniture are 95% of the way there.

2. Pull your speakers off the front wall to avoid excess boundary gain and enhance sound stage and imaging.

3. Treat remaining bass problems below 200hz with DSP or subs.

4. Skip broadband EQ over 200hz If you have decent speakers that already measure well anechoically. We primarily cue into the direct sound of speakers with ear/brain that a single mic has no way of doing.

5. Enjoy the music.

 

[Darkweb]

 

[CDMC]

The short answer is it all depends. It is like asking if your house needs air conditioning. If you live in Arizona, the answer is a definite yes. If you live in Nome Alaska, no.

What does the room look like? If it is all hardwood/tile/bare concrete floor, lots of glass, and minimal furniture, then your reverberation times are probably long and it needs treatment. I have a living room like that and even with a nice linear speaker (Salk Song 3) it sounds horrible because there is too much midrange energy. If you have a room that is wall to wall shag carpet, floor to ceiling heavy drapes, and lots of overstuffed furniture, not only could absorption treatment be detrimental, but you may need hard diffusion to liven it up.

The good news is you can get an idea quickly with a UMIK and REW. Run a sweep and check your RT60 decay times. If they are 300-400 ms, you are about ideal. Longer than that and you need absorption, less you need some hard diffusion to liven it back up.

GIK acoustics has an excellent set of clips comparing an overly lively room before and after treatment: https://www.gikacoustics.com/audio-examples-treated-vs-untreated-room/

And, just to give you an idea of how much rooms can vary, attached are my RT60 plots for my living room and office. The living room has hardwood floors, a big bank of windows with no curtains, and some room treatment, but not nearly enough resulting in the peaking you see at 2000 hz. By contrast the office only has one window with blinds, a big area rug, more furniture, and a few panels. Decay is nearly ideal.

 

[Wes]

I am trying to remember a quote from somebody (maybe Toole, but I think it was someone else)...

anyway it goes something like "most rooms are over-damped and under diffused"

 

[Snarfie]

Some years ago i started in my new house (the attic) to buy some gear to get a serious sound in that room. First i did was treating first reflections with self made absorption pannels (back, side's an ceiling around the close monitors) made of isover with a overall noticeable improvement lets say 20 % better sound. Way more than changing cables or buying a new amplifier, CD or DAC player. Than i combind the physical room treatment with roomcorrection software (Mathaudio Room eq). This combination made the whole listning experience atleast 70% better an i had no need for my subs anymore. The experience/improvement let me bought (again) also full range speakers.

 

[L33T]

Some years ago i started in my new house (the attic) to buy some gear to get a serious sound in that room. First i did was treating first reflections with self made absorption pannels (back, side's an ceiling around the close monitors) made of isover with a overall noticeable improvement lets say 20 % better sound. Way more than changing cables or buying a new amplifier, CD or DAC player. Than i combind the physical room treatment with roomcorrection software (Mathaudio Room eq). This combination made the whole listning experience atleast 70% better an i had no need for my subs anymore. The experience/improvement let me bought (again) also full range speakers.

May i ask, how did you combine? Do you mean compare before and after treatment applied or did you run this through something and perform EQ? (still learning

 

[Dj7675]

Some years ago i started in my new house (the attic) to buy some gear to get a serious sound in that room. First i did was treating first reflections with self made absorption pannels (back, side's an ceiling around the close monitors) made of isover with a overall noticeable improvement lets say 20 % better sound. Way more than changing cables or buying a new amplifier, CD or DAC player. Than i combind the physical room treatment with roomcorrection software (Mathaudio Room eq). This combination made the whole listning experience atleast 70% better an i had no need for my subs anymore. The experience/improvement let me bought (again) also full range speakers.

Did you take any REW measurements with your changes? It would be interesting to see. For example
1-No treatments installed with subs
2-All treatments installed with subs
3-All treatments installed with subs with eq applied
4-All treatments installed without subs with eq applied
It would be interesting to see the associated measurements for things like frequency response, decay (I think that is the right term) and impulse response which would show reflection info.

 

[Snarfie]

May i ask, how did you combine? Do you mean compare before and after treatment applied or did you run this through something and perform EQ? (still learning

Still learning too one of the reasons i'm a ASR member. First time i hear the (audio) sound in my attica it was horrible. Than i learnd to cancel first reflections. I used the mirror methode that Worked well with self made absorption pannels. Than i was advised on some dutch forum to use roomcorrection software REW incombination with a minidsp. Instead i used Mathaudio room eq found that software more handy an i did not have to use hardware as a minidsp. That brought the sound incombination with the already placed pannels for the first reflections to another considerble higher level. For what it is worth it is a quite subjectieve experience depending on how good or bad your or mine room acoustic is. Atleast Mathaudio room eq incombination with foobar2000 is freeware. Can't hurt to give it a try. Did work quite well for me.

 

[L33T]

Still learning too one of the reasons i'm a ASR member. First time i hear the (audio) sound in my attica it was horrible. Than i learnd to cancel first reflections. I used the mirror methode that Worked well with self made absorption pannels. Than i was advised on some dutch forum to use roomcorrection software REW incombination with a minidsp. Instead i used Mathaudio room eq found that software more handy an i did not have to use hardware as a minidsp. That brought the sound incombination with the already placed pannels for the first reflections to another considerble higher level. For what it is worth it is a quite subjectieve experience depending on how good or bad your or mine room acoustic is. Atleast Mathaudio room eq incombination with foobar2000 is freeware. Can't hurt to give it a try. Did work quite well for me.

Ah ok so your using room correction software inline with your audio player? I just use a pi/allo boss dac to stream audio, theirs no EQ or any changes made to the audio before it hits my amp, as my amp is Naim their are no adjustments available on that either. Or did i read your message wrong? I was planning on just taking measurements and making changes to the room then making more changes as required physically to the room.

 

[Snarfie]

Did you take any REW measurements with your changes? It would be interesting to see. For example
1-No treatments installed with subs
2-All treatments installed with subs
3-All treatments installed with subs with eq applied
4-All treatments installed without subs with eq applied
It would be interesting to see the associated measurements for things like frequency response, decay (I think that is the right term) and impulse response which would show reflection info.

Did try to make a REW measurment but could not get my mic correctly do a messurment with REW. Found it also to complex basicly i did not work for me. Still i made a Mathaudio Room EQ measurment it looks like this for the Vandersteens model 1 speakers realy don't need no subs now low is more than enough but only when roomcorrection is applied. Have a look at the mids an high's (grey line) where ther is sometimes a difference from almost 15db could you imagen what that does with your low. When leveling that see white line than suddenly there is more than enough bass.

 

[Snarfie]

Ah ok so your using room correction software inline with your audio player? I just use a pi/allo boss dac to stream audio, theirs no EQ or any changes made to the audio before it hits my amp, as my amp is Naim their are no adjustments available on that either. Or did i read your message wrong? I was planning on just taking measurements and making changes to the room then making more changes as required physically to the room.

Yes i'm running my audio platform on windows 10. If you can (for a test if room correction does anything for you) I would suggest dowload the Mathaudio room eq software incombination with Foobar2000 run it over a windows or apple laptop buy/use a good measuring mic do a measurment an listen what you already can accomplish without any physical addittions like absorption pannels. Decide after that what to do next for instance if you want to run room eq software independent from operation systems like windows or apple buy a Minidsp upload a measurment made with REW an you probably have more or less the same results as with Mathaudio room eq.