Why don't acoustics get more attention?

[OldHvyMec]

I have never been in a studio that wasn't treated. I had/have a few friends in the music making trade. I usually got stuck helping them
hang panels, place panels, diffusers, build diffusers and the hardest part, doing the darn ceilings with panels.

It is pretty amazing what you can do in a fairly normal rectangle room with 8, 10, 12+ foot lids. I've never seen a really tall ceiling in
a studio that didn't have hanging panels breaks at the 10-12 foot mark. EX: a warehouse space.

Today there is DSP and many people conclude "that is good enough." It is, if that is where you stop.

I liken that to stopping on a road trip at Jack-in-Box vs driving 5 miles MORE to a great Italian Restaurant.

You never know if you don't drive the extra 5 miles or in plain English. You never know until you experience a well treated room
with the same equipment in both treated and untreated rooms. People can say they have a good sounding untreated room all day long,
BUT it is only as good as it can be without the right treatment.

DSP is a wonderful tool considering what a person really has to go through to set up a room without using DSP at all.

The one exception is setting up kitty-corner and taking your time. It takes very little treatment and is all about the placement of equipment,
speakers, a curtain or two and the most important the setting position and getting the height right or the speakers tipped back (90+ %) correctly.

I remember when Decware set up their listening room and went from a purpose built design to a kitty corner design with great success.
There was a bit of a learning curve but it wasn't expensive because a majority of the treatment was placement. I've posted their result on a few
different forums through the years. I also remember as a kid in our garage band, we were FORCED (by where we set up too practice) to set up
kitty corner. It ALWAYS sounded the best when we played back our recording or were just listening to music.

Regards

 

[DVDdoug]

I read all up on this, but you can summarize his findings like this: Treat the floor and ceiling first, then the front and back, and leave the sides untreated.

He is not a fan of "over-treating" the room and for lower frequencies/room modes he prefers multiple subwoofers over bass traps. (Esthetic and practical considerations are a part of it.)

He LIKES EARLY reflections.

Here are some excerpts from his book:

For speech intelligibility - a crucial consideration for movies - it is early reflections that are the main contributors. Early refection energy arriving within about the first 50 ms following the direct sound has the same effect on speech intelligibility scores as an equal increase in the direct sound energy.

Early reflections also reduce the thresholds for detecting resonances in loudspeakers, making flawed loudspeakers more noticeable and revealing more timbral subtleties in music.

Early reflections can reduce the timbral degradation and speech intelligibility loss in the phantom center image.

Early (sound) reflections had the same desirable effect on speech intelligibility as increasing the level of the direct sound... Late reflections (including reverberation) are undesirable, but reducing them should not be the first priority, which is to maximize the total energy in the direct and early-reflected speech sounds. Remarkably, even attenuation the direct sound had little effect on intelligibility in a sound field with sufficient early reflections.

In the field architectural acoustics it has long been recognized that early reflections improve speech intelligibility.

Mixing engineers preferred the clarity provided by a lack of reflections, while mastering engineers preferred more reflective environments.

On the other hand, I've heard Ethan Winer described as a "studiophile." He seems to prefer a dead recording-studio-like listening room. The pictures on his website show LOTS of treatment. (His company, Real Traps, sells acoustic treatment.)

 

[Bjorn]

When we talk about acoustically small rooms, which all living rooms are no matter how big they are, early reflections are the reflections that generally arrive within 7-10 ms. Not within 50 ms, that's a long time span in a living room.

RTx measurements are not valid for small rooms. That was proven decades ago. Carpets are band limited treatment that should be avoided, at least for larger surfaces.

 

[kyuu]

It's pretty to understand why: effective treatments are bulky, generally not aesthetically pleasing, and require knowledge and skill to apply correctly. You also have to be careful not to kill desirable reflections. Doing treatments badly can be extremely counterproductive to getting good sound.

Upgrading equipment, on the other hand, is generally pretty easy by comparison. Particularly if you hang around ASR.

 

[kemmler3D]

I agree that cost should not be a limiting factor for people who are willing to spend thousands on speakers. However:

1) Aesthetics
2) Space / layout
3) Lack of experience with well-treated spaces
4) Lack of clarity on what to do
5) Don't own the place and don't want to commit that much to it

Are probably reasons people don't treat rooms more often.

I actually sold acoustic treatments for a living years ago, and I never decided to treat my own space until very recently (working on this currently) for all of those reasons as well as cost.

 

[goat76]

My experience with the application planing of room acoustic correction elements was that according to the layout software from a design/seller company was that I need to cover almost all of the room walls with panels including the ceiling. This would make the room acoustically completely dead. Good for a recording studio perhaps. Not for me. My speakers are rather good also with bass and music sounds good for my listening. Yes, it could be more perfect but if you think that live events which I attended are acoustically often also not perfect so I live with my untreated room. My opinion is that home room treatment is overestimated by the selling companies. Indeed the quality of the speakers make the most difference in sound. Last hint, for room acoustic treatment you need to find a real expert with experience and the right measurement tools. Otherwise you may loose money and don't get a good result.

If you are fairly familiar with using REW to measure your room for frequency response adjustments, it's not much harder to use the same group of measurements to see what needs to be done to treat the room acoustics. The only difference is that you now will focus on the time domain-related windows in REW as the "RT60 Decay" window and the "Filtered IR" window, instead of the frequency response.


Start by opening your in-room measurements and open the "RT60 Decay" window. Here you click on "Generate" in the lower left corner and a waterfall will be generated. Now you open "Controls" in the upper right corner and a window will pop up in the waterfall graph, click on "Calculate RT60 model" and a response curve will appear over the waterfall graph.

So now you look at that response curve...
1. Do you find it to have an even decay time from say 100 Hz and up to 11.5 kHz, or do you see a rising broadband trend somewhere over that range?
2. Is the overall decay time somewhat high, say way above 500 milliseconds?
The goal is simply to even out the decay times for the response, and also trim down the overall decay times to a lower level if they are on the high side.

So how to do it?
1. Look at the response curve and see what part needs to be treated.
2. Look for acoustic panels that have a good absorption coefficient for that range.
3. You don't have to fix everything in one go so just start with a few panels.
4. Re-measure the room and figure out what the next step should be.
5. Don't forget to have fun and listen to music while you do it. I'm pretty sure you will notice fairly large improvements with just a few acoustic panels.

You can see the change in the overall decay time I had in my room by just adding 3 more acoustic panels to a total of 5. The decay time was reduced and evened out, and the resulting sound is now more calm and relaxed.

So where to place the acoustic panels?
That depends on whether you have problems with strong first reflections or not, otherwise, you can just spread them out evenly in the room as that will even out the overall decay time anyway.

To see if you have problems with strong first reflection you can open up the "Filtered IR" window in REW. Here you see where the strongest reflections are, and by looking at the time scale at the bottom you see the delay in milliseconds. A delay of 1 millisecond is about 34 centimeters (or about 1 foot), so by looking at how many milliseconds the strongest first reflections are delayed you can easily calculate the distance, and by that figure out from what boundaries those reflections most likely come from in your listening room.
If the first reflections are 20dB below the impulse response they should probably not be considered a problem, but if they are way stronger than that, you should probably try to place an acoustic panel at that reflection point.

These are the first reflections in my room from my left front speaker. As you can see I have measured the extra travel time and figured out where those reflections come from in my room, but they are way below the direct sound at -19dB so I have not bothered to do anything about it (yet).

Under 100Hz is a mess in my room. I have chosen to take care of that with EQ as it would otherwise require extreme amounts of absorption.


And for the visuals...
I love how my acoustic panels look and they melt in well with the rest of the things in my room. One of them is even a painting, a great-looking piece of art.

 

[amirm]

To see if you have problems with strong first reflection you can open up the "Filtered IR" window in REW. Here you see where the strongest reflections are, and by looking at the time scale at the bottom you see the delay in milliseconds. A delay of 1 millisecond is about 34 centimeters (or about 1 foot), so by looking at how many milliseconds the strongest first reflections are delayed you can easily calculate the distance, and by that figure out from what boundaries those reflections most likely come from in your listening room.
If the first reflections are 20dB below the impulse response they should probably not be considered a problem, but if they are way stronger than that, you should probably try to place an acoustic panel at that reflection point.

This is not a wise strategy. The Impulses are much more correlated with high frequencies than overall energy. To wit, two identical reflections in such graphs can sound very different. Further, perceptual effects of these reflections is very different. Depending on the direction of reflection, what arrives at the two ears differentially is very different.

I have seen people drive this strategy to the ground to get rid of all those impulses. Then one day they remove all the absorbers and are amazed how much better the sound is then!

 

[privilege15]

I'd say go for the early reflections first and after that the room in general. And then of course DSP for the bass

To clarify, floor and ceiling early reflections - YES (treatment always). As for the side walls, if the speakers are bad (poor directivity) then - YES (treatment necessary), if the speakers are good (outstanding directivity) then - NO (no treatment required).

 

[terryforsythe]

It seems like "nobody" wants to get fiberglass panels for their room even though they're far cheaper than high end speakers, they make spaces more comfortable, and they can look great (so they serve as decoration too). Why is this?

Try explaining that to the boss (a.k.a., my wife).

 

[privilege15]

Try explaining that to the boss (a.k.a., my wife).

My "boss" accepted a little mess after she heard the DIFFERENCE before and after.

 

[goat76]

This is not a wise strategy. The Impulses are much more correlated with high frequencies than overall energy. To wit, two identical reflections in such graphs can sound very different. Further, perceptual effects of these reflections is very different. Depending on the direction of reflection, what arrives at the two ears differentially is very different.

I have seen people drive this strategy to the ground to get rid of all those impulses. Then one day they remove all the absorbers and are amazed how much better the sound is then!

Those people probably overdid the acoustic treatment in their rooms. It's always about finding a good balance to your liking, that's why I think it's a good idea to introduce acoustic treatments one by one instead of trying to fix everything in one go. That way you will know if you are moving in the right direction according to your preferences.

I don't consider getting rid of all reflections in a room a good idea. While I want to hear most of the acoustic information in the recording itself, I still want the envelopment that my room will add to the overall perceived sound. All the acoustic treatments I've done to this point have made things better, they have "calmed down" the overall sound in a way that I like, but as I said, I'm very cautious and take it step by step to not overdo it.

 

[Multicore]

Try explaining that to the boss (a.k.a., my wife).

Before opening negotiations about bass absorbers with the boss, you could first propose installation of decoration. How about a nice looking wool rug? Enjoy choosing it together with the boss. Do the installation. Enjoy your earned points but don't spend them yet. At some later date install the absorbers behind the rug.

Just an idea.

 

[terryforsythe]

Before opening negotiations about bass absorbers with the boss, you could first propose installation of decoration. How about a nice looking wool rug? Enjoy choosing it together with the boss. Do the installation. Enjoy your earned points but don't spend them yet. At some later date install the absorbers behind the rug.

Just an idea.

Thanks for the suggestion, but that would be a no go. The boss has the room decorated just as she wants it. I was fortunate to even get her to agree to small stand mount speakers. During the renovations she actually told me she wanted no speakers in the family room. I had to find speakers that closely match our decor to get her to concede.

 

[Bugal1998]

To clarify, floor and ceiling early reflections - YES (treatment always). As for the side walls, if the speakers are bad (poor directivity) then - YES (treatment necessary), if the speakers are good (outstanding directivity) then - NO (no treatment required).

I have blind tested (not double blind) treating vs not treating floor reflections and found I strongly prefer them untreated. My spouse shares the same unambigious preference. YMMV.

Wasn't able to blind test ceiling reflections, however, I have A/B tested and didn't have a strong preference. One school of thought says they narrow the apparent source width, while another says they tend to not be perceptually irrelevant; my anectdotal experience suggests it may be the latter.

Sidewall reflections are more subtle in my experience, but I used to believe I preferred a dead sounding room, but now prefer the added liveliness of minimal treatment with well behaved speakers. I would also argue that no listening room should be built around anything but well designed speakers (spend on speakers before treatment).

I'd say go for the early reflections first and after that the room in general. And then of course DSP for the bass

It is often said to treat early reflections, then treat the rest of the space for a consistent RT20, RT60, etc. across the spectrum. An alternate approach is to minimally treat early reflections to prevent image shifts, and then leave the rest alone. I have tried both in my space and prefer the experience using the latter approach. People have seen my room measurements and said, 'you need to treat the decay time of the upper mids to make then consistent with the rest of the spectrum'. So I did. And after living with it for a month I just didn't like it. Clarity was maybe MAYBE inceased a perceptible amount, but spaciousness and envelopment was sharply reduced. No thanks. As always, YMMV.

Edit: My room is a dedicated space without standard household furnishings.

 

[goat76]

People have seen my room measurements and said, 'you need to treat the decay time of the upper mids to make then consistent with the rest of the spectrum'. So I did. And after living with it for a month I just didn't like it. Clarity was maybe MAYBE inceased a perceptible amount, but spaciousness and envelopment was sharply reduced. No thanks. As always, YMMV.

Can you share the measurements of the treated vs the untreated response? Preferably graphs for the time domain.

 

[Bugal1998]

On the other hand, I've heard Ethan Winer described as a "studiophile." He seems to prefer a dead recording-studio-like listening room. The pictures on his website show LOTS of treatment. (His company, Real Traps, sells acoustic treatment.)

I started out in 'camp Ethan'. It's so easy to be lured in by the easily heard clarity absorbtion can enable. But with time and experience I discovered that, for me, the highly analytical experience offered by absorbing early reflections is like watching a display with the sharpness set too high; it was striking and pleasing at first, but it eventually became unatural and off putting. Tradeoffs for sure, but I find a somewhat livelier space immensly more enjoyable on the whole; and I listen for enjoyment.

 

[terryforsythe]

People have seen my room measurements and said, 'you need to treat the decay time of the upper mids to make then consistent with the rest of the spectrum'. So I did. And after living with it for a month I just didn't like it.

I took measurements of my family room and my office. My office has RT60 decay much closer to what I have seen asserted as being optimal, but I prefer the sound in my family room (pictured above, but when I have the speakers pulled out to their optimal listening positions).

The speakers in my office are KEF LS60 Wireless, with CamillaDSP for room correction. The speakers in my family room are heavily modified Elac Uni-Fi Reference with a subwoofer and a miniDSP Flex HTx for active crossovers and room correction.

 

[Multicore]

she actually told me she wanted no speakers in the family room

what was her idea: no TV? pictures without sound?

 

[bachatero]

I have seen people drive this strategy to the ground to get rid of all those impulses. Then one day they remove all the absorbers and are amazed how much better the sound is then!

But hold on, what about headphones? They are essentially impulse-free but nobody's complaining about how that sounds.

 

[terryforsythe]

what was her idea: no TV? pictures without sound?

She wanted the TV, but wanted to use the TV's internal speakers for audio.