Is room treatment a science?

I keep it simple: 1. Walk around your room and clap your hands. If you hear echoes, put something (I use foam panels) on one of the opposing walls. 2. Put panels on the "early reflections" areas close to your speakers (to kill the early reflections). 3. If the overall sound is unfocused, use panels until imaging improves. 4. If sound starts to sound flat or dull, remove some panels -try different combinations to see which sound best.
Also, try to avoid large pieces of glass (use curtains, etc.) -avoid reflections.
If possible, try to make the room symmetrical. Don’t have the left speaker projecting along a solid wall and the right speaker next to the dining room (open concept -no wall). try to make things equal on both sides of the sweet spot. So yeah, it's pretty much a science. But in the end, make it sound right to YOU. Good luck!

Actually trial and error is fast, cheap, and easy. Its what I did and highly recommended. Provided you do it the right way. Otherwise yes it can be incredibly expensive.

Dweller nailed it on the slap echo. Here's how to do it methodically, cheap, and easy. Do what he said, with OC703.

Owens Corning acoustic panels are industry standard. Thicker panels absorb lower frequencies but a couple 2'x3'x1" panels is probably all you will need. They are cheap and light and easy to cut with a box cutter. Here's a picture of my room from many years ago when I was still experimenting. https://www.theanalogdept.com/c_miller.htm Notice lots of yellow OC703 panels on the walls. They are temporarily held with push pins. That's how easy it can be. 

Notice the dark gray panels in the corners. Those are the same OC703 only cut to fit and covered in fabric. DIY acoustic treatment. Very effective but without making the room sound dead. 

Now here is more recent. https://systems.audiogon.com/systems/8367 No more big panels on the walls. Just the corner tunes. Much better! Its rare someone comes in my room and doesn't comment on the acoustics. Its not dead, not lively, but everything is crystal clear.

Acoustic treatment is a balancing act. I don't need side panels to catch the first reflection, probably because my speakers are more than 4' from the side walls. If I did they would be as small as possible, no more than one to two feet square. But this is why you buy the panels and experiment with them like I did. Its so easy you can't believe it.

That's the old school acoustic treatment method. Its great however only if DIY. Because the minute you talk about spending more than to buy a few cheap panels you'll get much better results going with something like Synergistic HFT. So start cheap, and build from there.

Yes.  Room acoustics is a science and is written about by much smarter and more accomplished people than I.  I like to read Floyd Toole when I want to pretend I'm smart.  Otherwise I ask GIK Acoustics for advice.

I will say after lots of measurement and experimentation that treating your room well is never a mistake. My room treatments have outlived everything else I own. It is by far more productive to treat the room than start swapping speakers, cables and amps. 

Great ideas!  The project begins. I thank you!

Trial and error. Big problem. It’s not really science. What’s required in order to have a glimmer of hope of finding the absolute best solution for room treatment is to employ a SPL meter and test tone generator such as 315 Hz, for example, on a test record or CD. That way you can precisely locate the problems in the room, a great many. The primary acoustic anomalies in the room are sound pressure peaks more than 6 dB above the average sound pressure in the room - e.g., room corners, standing waves, first and second reflection points, sound pressure peaks behind the speakers, peaks in the 3D space of the room.

Room echos can be easily identified using wood blocks and walking around the room clacking the blocks together or clapping your hands 👏  until you hear the distinctive echo. Once you have treated the room, use the speaker placement track on the Test CD or LP to find the absolute best speaker locations. If you add more room treatment at a later date, tiny little bowls, Mpingo discs, whatever, you need to reestablish speaker positions as room dynamics will change. But, gentle readers, trial and error for room treatment - like its cousin speaker placement - is like trying to solve X number of simultaneous equations in X + N unknowns.

Yes room treatment is an actual science, if you look at recoding and mixing studios you will see.   But it is very straightforward and pretty easy to do. 

As stated above, GIK can be a good resource if you need a consult and product.  If you have an idea on what you need, Audiomute is another good and affordable product line.  If cost is an issue, most all of this can be a DIY project.  Don't over do it, stick with some fundamentally accepted treatment suggestions to start and go from there.  Good luck in tuning your room.

The above suggestions have schooled me. Your explanations have been tangible and easy for me to understand.

Thank You!

Another vote for GIK Acoustics and their invaluable advise. They have wide variety of Acoustic panels, basic panels are inexpensive and well made. IMO, they far outweighs the DIY panels. I did my room in two phases and couldn’t be any happier with the results.

As others have pointed out, start with basics and then add more later, if needed.

Mr Squires nailed it.   "I will say after lots of measurement and experimentation that treating your room well is never a mistake." 

Room is part of the system. For me the largest and most revealing improvement in SQ came from treating the room.  

I gotta do room treatment next.  Prolly be a year or two but gotta do it, methinks.

Yes of course acoustics is based on science and nothing else.   Lots of good books on how to tackle it correctly. Applying it to a specific room to achieve a specific goal is the challenge. 

Big problem. It’s not really science.

Lol! Science. Clearly a stranger to you. Allow me to introduce you to the subject.

Sound travels in waves. Like all waves when they encounter changes in density they reflect or refract. In other words sound bounces off walls just like light reflects off a mirror.

Another thing waves do is cancel and reinforce. When two wave crests meet we get reinforcement and the resulting wave is greater= louder. When they cancel we have a null or dead spot. 

The length of a sound wave is related to its frequency. The higher the frequency the shorter the wavelength. The wavelength of sounds we can hear ranges from around 50 feet or more at the lowest bass to less than an inch at the highest treble.

So in the scientific view of acoustics we have a lot of different waves propagating back and forth across the room. Our scientific goal is to minimize the cancellations and reinforcements in order to hear the original signal as clear and undistorted as possible. 

One way to do this is attenuation or absorption. We can do this with a medium such as a fiberglass panel. Sound waves move the fibers in the panel. This movement transfers the mechanical motion of the air into mechanical motion of the fibers according to Newton's Law, with the thickness of the panel determining the peak frequency of absorption. Because, remember, wavelength.

Too much of this and the room sounds dead. If only there were some way of spreading the waves around, dispersing them more evenly, so we can keep that spacious sound without so much of the troublesome reinforcements and cancellations. 

Science to the rescue! Since we know sound is waves we can build panels to diffract the waves. They can be small flat surfaces of differing heights or large flat surfaces of differing angles. All these things audiophiles will have seen- and who knows maybe even you too. Now you know the science behind them. 

Why did mc misquote me? Why is he putting words in my mouth? Maybe because I was attacking his foolhardy trial and error routine, which is the opposite of scientific. Maybe a ....reading comprehension issue, who knows? Careful, don’t blow a head gasket. 🤯

My two suggestions are, talk to GIK Acoustics or learn everything in Floyd Toole's book:  Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms


https://amzn.to/35WboEV


and ignore the trial and error people. :)


Best,

E

What does the ideal room even look like. If you can't Precisely answer that question, then you have no hope of stumbling across the right answer...and certainly not by looking at anything that 'seems like a good idea'. The physics will necessarily prove to be too involved to guess at. Nothing at all will be right until you get the bass (100 Hz and below) right. No matter how much you spend on the 100-Hz-and-Up solution - if you spend it before you get the bass exactly right, whatever 100Hz-and-up solution you've already implemented is Guaranteed to be wrong and will have to be entirely redone once the correct 100-Hz-down solution is established. No matter how much money you dumped into the 100Hz-Up, if you've already done the 100Hz-and-up thing, it will All have to come out and you will have to start that part over from scratch. 

Also, the bass is very hard and usually expensive to get right even in a good room and is too poor a value to attempt to solve in a bad room. If you have a "bad" room (almost every room is bad), you should walk away from the idea of treating it altogether, period. You will have no other real choice than to consider getting a good room. But, there is more to getting the bass right than room volume (although that's a start). As I say, you will need to know what the ideal room looks like. Drywall over 2x4's are not it...neither are 8 ft ceilings. If you have either of those things, you are already starting off in a supremely expensive hole. And about 98% of all the "bass traps" out there cannot fix the problem (never buy Anything advertised as a "bass trap").

If you find yourself in the 'I-think-it-should-be-easy-if-you-just-follow-logic-and-common-sense' camp, then go to acousticfields.com and watch Every video that Dennis Foley has made over the years and then tell me how easy it looks...that should pretty much slap you around some. As others have pointed out, you can't approach the right solution (the right one being the only one that truly works) by guessing or without access to expertise in the field. The physics just won't allow an easy, affordable answer...that really IS a pipe dream.

If you cannot afford the right solution or you would rather consider the wrong solution because you know it's cheaper, then financially you are much better off walking away from all but the very least expensive treatments at the first reflection points and calling it a day.

Take a look at the Realtraps website for good info and excellent, well engineered products:

https://realtraps.com/

So in the scientific view of acoustics we have a lot of different waves propagating back and forth across the room. Our scientific goal is to minimize the cancellations and reinforcements in order to hear the original signal as clear and undistorted as possible.

Miller just described an anechoic measurement chamber.  Hahahahahaha.

It is like medicine an art based on science.....

Because of the human factor….Remember that even if the ears are less accurate than a singular dial corresponding to a particular set of a measure instrument, the ears can coordinate multi measuring coming from different kind of apparatus about all dimensions of perceived sound experience (tonal accuracy, imaging etc)......The ears are the only judge and guide through audio....

There is 2 way to act on the acoustical field of a room:

1-The PASSIVE way with some different materials absorbing or reflecting one at different locations... Most people use only this way...I use homemade materials or low cost one at strategic locations...


2- There is the ACTIVE way that is more complex but very rewarding...

a- I use a grid of active metal resonator (30)
b- I use 20 Helmholtz bottles of different sizes
c- I use a grid of connected stones and crystals
d- I use a grid of cheap 8 Schumann Generators modified with crystals and stones...
e- I use a grid of 70 little bells or cones of 2 different sizes(7mm or 9 mm) with some nano Herkimer diamonds in them ...This grid of cones stabilize for the brain the recognizing process of complementing sounds waves coming with the competing obstructing distorsions created by the topology of the room accidents...This is not science only my way to convey my understanding...

The embeddings on an audio system in his mechanical resonant field is 20 % of the S.Q.
The embeddings of an audio system in the electrical field of the house is 25 % of the S.Q.
The embeddings of an audio system in the acoustical field of the room is 55 % of the S.Q.

The % varied relatively to the methods used, but these indications gives an idea of the general results after my experiments ….

The final results are a very high S. Q. for a ridiculous cost....All my materials are homemade created or bought for peanuts....But the result is in no way cheap.... :)

You can compensate for a modest audio system relatively to a very costly one with the controlling methods linked to these 3 embeddings ,especially the acoustical one....

A vintage low cost amplifier but good product of the past for example, in a controlled room, may sound way better than a way more costly one in a non treated room..... This is the only thing I know for a fact about audio....

Upgrading is most of the times only a game , but if you dont have money, it is not necessary to spend any great amount to buy Hi-FI…. The contrary opinion is "mostly" a marketing myth.... :)



In 2 words:
The acoustician is more important than the electronical engineer.... :)

So in the scientific view of acoustics we have a lot of different waves propagating back and forth across the room. Our scientific goal is to minimize the cancellations and reinforcements in order to hear the original signal as clear and undistorted as possible.

Miller just described an anechoic measurement chamber. Hahahahahaha.

Anechoic means no echo. Its a fact. You could look it up. Here, I’ll do it for you: https://en.wikipedia.org/wiki/Anechoic_chamberNo echo. No sounds going back and forth. Now what I said: "a lot of different waves propagating back and forth across the room." Literally the opposite of an anechoic measurement chamber.  

What you just described erik_squires is literally the opposite of what I said. You literally do not know the difference between echo and no echo. Now why am I not the least bit surprised by that.....

I definitely agree with @mahgister when he says that the room's acoustic problems (peaks and nulls at the very least) can be positively influenced and very effectively smoothed out and flattened to a substantial degree actively as he says, even without ever resorting to EQ. 

That's an additional topic, but one that's definitely relevant...not nearly as unrelated as you might first think.

geoffkait,

"...test tone generator such as 315 Hz, for example..."

Is there a reason you picked 315 Hz or it can be anything else? Maybe a range that would be the most helpful? Wouldn't different frequencies act differently in different parts of the room?

The sciences of acoustics and psychoacoustics are applicable to room treatments.

I agree with @erik_squires ’ recommendation of Floyd Toole, in particular his book "Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms". Imo the third (most recent) edition is the one to get.

Another excellent source is Earl Geddes. His book "Premium Home Theater: Design and Construction" is now available for download free. Don’t be put off by the title - most of the book is applicable to high end two-channel. Just skip the chapters which obviously don’t apply to home audio:

http://www.gedlee.com/downloads/HT/Home_theater.pdf

Chapter 5, "Room Acoustics", is the most obviously applicable, and includes sections on Spacious, Localization, and Timbre.

I used to engage in armchair-quarterbacking recommendations of room acoustic treatments, until I spent some time in couple of rooms that had been treated by a real professional, Jeff Hedback. A real professional acoustician can tell you where you need diffusion, absorption, and reflection, and how much. (By way of analogy, a professional crossover designer will determine where you need inductance, capacitance, and resistance, and how much.) Jeff is still affordable and his company is called Hedback Designed Acoustics. Here is an article he wrote for GIK Acoustics, it is about much more than just diffusion, imo it’s very much worth reading:

https://www.gikacoustics.com/diffusion-by-jeff-hedback/

Duke

Duke,

Thanks for sharing the two article, very informative indeed. Anyone serious about audio should address room acoustics before they think of upgrading their components. GIK Acoustics value driven products and their true desire to help their customers is commendable.

Actually anechoic means no echoes AND no reflections. All reflections are not echoes. In most rooms some reflections are beneficial whereas echoes are not. It’s probably not a good idea to turn your room into an anechoic chamber, but who knows? I certainly never tried. I keep seeing people saying that you shouldn’t. Echoes are easy to eliminate by using the clap hands 👏 method. It’s not rocket science, guys. 🚀

Sorry for such stupidity but I've got a setup with some xrt 30 Mac speakers in a 40 x 40 room probably do not require any room treatment for this type of space any insight thanks

Is a $4,000,000,  2000 seat auditorium trial and error or scientific.?

"Is a $4,000,000, 2000 seat auditorium trial and error or scientific.?"

It depends how they went around the volume of bodies expected to be in and material that clothes would be likely made of while there.

yes, it's a science. But you can diy, cheaply and simply and hear an improvement/difference.
It's easier to take brightness and echo out of a room, I would think, than the other way 'round.
Having a large rug on the floor helps.
Artwork on the walls helps.
Seating arrangement helps and the style of seating helps too.
I really notice a difference by pulling the curtains across the sliding glass doors. Stops reflection and harshness..

That Geddes book is a gold mine! If only I had known- and it had come out a dozen years earlier! Lol!  Oh well at least I got the solid wood exterior door with weather seal!! 

Yes, room treatment it is a science.  Do yourself a huge favor, and download REW software and learn how to use it and interpret the data.   Start by optimizing the position of your speakers and listening position, then begin to add treatments addressing first reflection points, slap echo etc.  Sometimes, you can get surprising improvements by careful positioning of room treatments other than the listening position.  

You can do a certain amount without measuring, but it can be slow progress.   Most of us can discern small differences for the better or worse by ear.  But after a while, it can get to be mind boggling to keep track of.  There are so many variables.   I like graphs that I can archive along with notes on listening impressions associated with a given room configuration.  I can tell you my room is orders of magnitude better than when I started, and I never would have gotten where I am now without REW.  If you invest a little time and effort you won't be sorry.

Millercarbon wrote, "That Geddes book is a gold mine! If only I had known - and it had come out a dozen years earlier!"

Yes it is a gold mine, under-appreciated probably because it has "Home Theater" in the title.

I’ve been in Earl’s home theater room several times (mostly listening to two-channel). It is one of only two systems I have experienced which can pull this off: It can play so loud that you literally have to shout into the ear of the person next to you in order to be heard, but the sound is so clean that it doesn’t hurt your ears! This actually makes it kinda dangerous, as the SPL can be much higher than you realize. The only other system I heard which could pull this off was over ten times the cost.   The combination of natural timbre, smoothness, imaging precision, and spaciousness in his room is amazing.   And his bass is pretty good too! 

Duke

Yes.

rhodes, well, both. (4mil$, 2000 butts in seats....generally not totally filled).....

When one enters that sphere, the acousticians start with scale models and 'mini-mics', trying to define where to start.

When the actual structure is nearly done is when the science butts into the art.  There's been spaces that looked great 'on paper' that sucked in reality and triggered major 'change orders' and compromises.

Sound in a given space, large or small, is generally a compromise.  In a home, unless one has built for the intended space, there will be trade-offs....and even with the 'built space'....MC alludes to that; he began with 'x', but lives with 'z' happily...

I'm approaching having to 'make that deal' in the near future.

But, for the time being, I just 'run what I've brung'...or have. *S*

It is a science and it’s not all about absorption. If you have corners, if you have 1st reflection points, then you will need treatments. If you have bass issues, after you have tried positioning the speakers with no cure, your corner absorption pieces will need to be fairly large, small panels only deal with higher frequencies. Also, diffusers can be both a diffuser and an absorber. IMO, work with GIK or ASC or both to get a good idea on what’s needed. Also, watch the Dennis foley YouTube videos on this subject, these guys are the experts

Yes, it’s a science. Reading the books and asking experts is always a good approach.

A few easy tips:
- “ slap echo” just means clapping your hands in center of room and
     listening for echo.
-if a ping pong ball will bounce off a surface so will sound.Glass 
 sucks.
- wool rugs work.
- book shelves on side walls with uneven books break up
  waves and work.
- try closing doors.

You can probably get a reasonable result that you are happy about by simple self administered methods or you can spend money up front and get an audio guy (they are normally involved with setting up home theatres) to come in and analyze the room for you.

The latter would certainly cost more up front, but would also prevent you trying things that didn't work, going down dead ends and spending money on the way. hard to know which would work out better and cheaper.

Many sophisticated descriptions of acoustician principles.
My main system is in my family room and my wife would never agree to have panels and other acoustic treatments on the walls!
I have experienced room treatment as extreme as a half million plus spent to create a dedicated room with acoustic walls floor and ceiling! For me, the most WAF friendly and very effective treatments are ASC products. Their bass traps are elegant grey cylinders that can be placed behind to the corners of the speakers. I don’t have them now but have used them in the past to great effect in focusing the sound and tightening the bass.

a lot of good advice above. I built  28 x 17 room from scratch with acoustics in mind. I wanted only minimal wall treatments. +1 on ASC tunable cylinder traps. very versatile and effective. trial and error will definitely get the "low hanging fruit" and produce a noticeable difference. but it is a science to clean up a room while keeping it lively.  I had my room tested and identified resonant frequencies and where they existed.  Placed absorption & diffusion treatment as needed for the specific problem frequencies. I had everything tested and made through Artnovion. Color & design coordinated with room so it looks beautiful in addition to sounding great (to me). I think a good room treatment is like upgrading every component you have at once. Good luck 

There are many good responses explaining the science and approach to this problem.  So I don’t have anything unique to add.  I do highly recommend you look at the Acoustic Sciences Corporation (ASC) products.  I have used them for the last 15 years.  They have traveled with me to three different houses, five different listening rooms.  The ASC Tube Trap is simple and elegant.  Each Tube Trap is designed with an absorptive side and a diffusion side.  This is important in that the solution for tuning a room is not always absorbing unwanted reflections or frequencies.  By using a combination of absorption for removing unwanted bass reflections and diffusion for addressing mid and treble frequencies you can create great focus in the room, while still creating a sense of size and liveliness.  Good luck on your journey.  Cheers!  

Bout time I spoke up.
Yes, it is science. No, there is no perfect room. Yes there is a method to the madness. Finally, there is always a trial and error period based on what the individual likes to hear. 
Everything is based on reflected sound. Early reflections are always bad. They interfere with localization and detail. They "smear" everything and can alter frequency response. Late reflections can be used to advantage. You can generate "echos" that will give you the sense of a larger space.
Sound bounces of boundaries just light light off a mirror. You are only interested in what sounds get to your ears at the listening position. So, you work in reverse. Sit in you listening position and have a friend hold a large mirror against the walls around the speakers. Have him move the mirror at your head level across the wall slowly. When you see the reflection of the speaker in the mirror, mark the wall. That is one early reflection point. Continue around the three walls adjacent to the speakers until you find them all. With point source speakers you have to worry about the floor and ceiling. Those who have line source speakers only have to worry about the walls. Those of you lucky enough to have Line source dipoles only have to worry about the wall behind the speakers. You can also find secondary and tertiary reflection points this way. I use acoustic foam tiles at the early reflection points because it is cheap and easy to use. Once you get below about 150 Hz things get way more difficult. Bass has a lot on energy. Any of you heard  sonic boom? Impressive to say the least. In a room bass just keeps bouncing around and everything has a resonant frequency, the walls, the cabinets and that picture you have hanging on the wall. It took me 6 months to finally get my picture screen quiet. Still if I turn my satellites off and just run the subs the whole house sings. Fortunately the satellites mask the symphony. There are ways to deal with the bass problem to a point but all of them are imperfect. Most important is using multiple subwoofers then comes digital room control. IMHO everything else is wishful thinking. 
My best advice is buy some of these  https://www.parts-express.com/sonic-barrier-fwp121-sawtooth-foam-sound-damping-for-enclosures-and-studios-12-x-12-x-1---260-546  , find your early reflection points and have at it. Never buy fewer than two sub woofers. One sub just is not worth it. You are better off without.

Best of luck,
Mike

There is a gentleman who has a YouTube channel that I watch regularly, the channel name is Acoustic Fields, and Dennis Foley is the the person who does these videos, and has a company of the same name who does very high end acoustical installation, and more. Well worth your time, and yes indeed, it is a science.

Just today he went over a very basis goal you must meet before anything else can be considered; equal sound level/pressurization within your room. This was very interesting, breaking up the room in several sections, in which all locations must be close to equal in volume, or pressurization. One thing he stressed is that the area behind the speakers must have an equal DB level as your sweet spot, or a far corner of the room. I said to myself, ‘oh man, I bet mine is a mess’. Took out the DB meter on my phone, and walked all around my room. I was surprised how equal my room was, but nothing near what he accomplishes on his projects, I’m sure.

Anyway, a very interesting guy, who is nice enough to provide some basics from a pro in high end acoustical treatment installs. Well worth your time.

Stillpoint Apature panels buy at least 4 asap for the best sound.Make a dash spend some cash!!