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The Top 5 Room Acoustic Problems You Face In Your Studio

Dennis Foley August 11, 2014 No Comments

This blog has been updated to reflect new information in regards to room acoustic problems you may face in your studio, updated on 11/11/19.

There are 5 top room acoustic problems that people commonly face in recording studios the world over. But to understand them you first need to accept that there are three, and only three, things that happen to sound energy within your studio. It can either be absorbed, reflected, or diffused. That’s it. There are no other characteristics that we can assign to sound energy in our studios, unless we come up with some new laws of physics.

The Top Five Room Acoustic Problems You Face In Your Studio

In your studio, you need to be concerned with all three. All three have an impact on your sound within your room whether it is a project studio that you set up in a spare bedroom or a full blown brick and mortar studio with different live, voice, and music rooms. Lets start with absorption and those nasty low frequency “bass booms.”

Room Mode Pressure

Room Mode Pressure

1. Low Frequency Management

The first acoustic reality and treatment myth that we must address is low frequency energy management. This is the most important element of the top 5 room acoustic mistakes you are making in your studio. Lets start with an accurate definition.

Low frequency energy is any energy that is less than 100 cycles. This definition comes about because you need different absorption technologies for treating energy above 100 Hz. in small room acoustics than you do below 100 Hz. These sound absorption technologies require drastically different approaches to effect treatment and management.

Treating energy below 100 Hz. requires mass and depth or distance. Treating energy above 100 Hz. can be accomplished with technologies that take up much less space and can be wall hanging units like foam. The difficult management happens below 100 Hz. Get that out of the way and your mids and highs will pop. As such, low frequency treatment provides a good dividing line from a room acoustic treatment perspective so let’s take a look at what you need.

Treatment A Must

Low frequency energy, < 100 Hz., must be treated. The acoustic power of this energy is covering and smothering certain frequencies within your music that you are not hearing at all because of these room modal issues. Therefore, it is a musical imperative that they must be dealt with. You would not put up with a piece of gear that did not reproduce certain frequencies in its output and likewise you can not put up with that in your room. This is your product that you produce which reflects your musical talent and production skills. Mess with that at your own risk! You can’t have things missing here. There is a lot of important music from 30 Hz. – 50 Hz. and it must be heard. It is the foundation on which the rest of the sonic presentation exists for. Do not short change this area. Your product will suffer and you will miss sounds that you need to hear during the recording and playback process.

Lateral Room Reflections

Lateral Room Reflections

Treatment Myths

The treatment myth is that you can get rid of low frequency issues in your room by placing a box filled with building insulation or foam (otherwise known as a bass trap) around your room. First of all, all you can do with frequencies below 100 Hz. within a room is manage them. Certain lower frequency issues can never be eliminated and thus a reason why some people move to larger rooms. Any concern for dealing with this area of the top 5 room acoustic problems you are facing in your studio, must be taken seriously.

Make Room Smaller

It’s actually counter intuitive but in order to manage your low frequencies, you must make your whole room smaller using the correct technology, namely, diaphragmatic absorbers. You make it smaller by adding this proper low frequency technology around the room boundaries. You do not use boxes filled with building insulation or foam (the aforementioned bass traps…which are good for one thing, trapping dust!). They do not have the acoustic horsepower to deal with 30 Hz. 40′ waves of energy. Using these technologies is like using a feather to stop a tornado.

2. Appearances Are Deceiving

The second myth is that you can set up your studio any way that looks good or “cool”. Unfortunately, the laws of physics don’t give a damn about “cool”. They are simply there to dictate what you can and can not do. I see studios everyday that put decor ahead of acoustical needs. I have a simple question in such situations… “do you hear with your eyes or your ears?”

So here are some simple rules.

i. Speakers must be equal distance from both right and left channel side walls. You can not have one speaker closer to the side wall than the other.
ii. Your seated position must be located a certain distance from your speakers and rear wall.

Here is why.

Broadband Diaphragmatic Absorber

Broadband Low frequency Diaphragmatic Absorber

Sound Energy Is Constant

Sound energy moves at a defined speed, around 1,130′ per second. Reflections from the side walls will be slower than the straight line sound that comes directly out of your speakers to your ears because it has to travel a bit farther leaving the speaker and then striking the wall. It is that straight line sound that is the purest. It does not contain room sound, but it soon will.

Side Wall Reflections

Reflections traveling from both side walls will transverse the direct sound or straight line sound coming from your speakers. It is the proper slowing down of this energy that you must accomplish with correct room treatment technologies. You need the sound energy striking the side walls to have even time signatures, so you can apply the correct rate and level of sound absorption technology. To achieve even time signatures, you need even distances. This is another critical issue in the top five room acoustic mistakes you are making in your studio.

Sound Triangle

Your speakers and listening position are a “sound triangle”. The speakers and listening position form the apexes of a triangle that must be moved as a single unit. It is that positioning of all 3 items that must balance with room dimensions and low frequency pressure levels. There is only one position of the “sound triangle within your room that will give you the best frequency response within your room. Most of the time the best position is not what looks the best within your room. Are you concerned with appearance or good sound?

3. Watch Rates And Levels

The third common acoustic problem that we see in most studios is that absorption rates and levels for sound absorption treatment can be all over the map. A lot of people will buy a product that absorbs a certain amount of energy and that since it performs on a limited frequency basis, they assume it can do everything acoustically within their room. It can not, no matter what the manufacturer claims. Remember those laws of physics?

Minimal Absorption

You must absorb at a rate and level of absorption that does just enough to minimize the “acoustical damage” it causes upon your signal. There is no need to eliminate large amounts of your sound energy through absorption. Converting acoustical energy to heat using the process of absorption, eliminates sound forever. Ever been in a room that is just too dead? It is called “dead” for a reason.

Acoustic Fields Quadratic Diffuser

Acoustic Fields Quadratic Diffuser with Base

Reflections Are Rate and Level Sensitive

Reflections from your room wall or boundary surfaces must be controlled at the correct rate and level using sound absorption technology. Most companies will tell you to absorb as much energy as you can to manage the reflected energy. If you do this, you “destroy” the acoustic energy and convert it to heat. You do not want to “destroy” sound energy in order to manage it, at least not all of it. You need to take just a little from each reflected frequency, that it slows down just enough, so that its arrival at your listening or monitoring position is less than the direct or straight line sound from your monitors or speakers. You want the time signature of each reflection to be below the time signature of the direct sound.

4. Don’t Forget Ceiling and Floor

Our fourth myth is that the ceiling and floor do not contribute any reflection issues that must be managed. Do you have ceiling treatment in your studio? Most do not. It is very important. Remember your side wall reflections that we needed to slow down, so that they arrived below the time signature of your direct straight line energy from your speakers? Well guess what, the ceiling and floor reflections actually arrive before the side wall reflections do.

Ceiling And Floor Closest Surfaces

Think about it. You are closer to the floor and ceiling in small rooms than you are the side walls. Floor and ceiling reflections enter your mix and music play back presentations. They must be managed with the same approach as the side walls. They account for 15 – 20 % of what you’re hearing. They need to be respected and treated.

Side wall Absorbing panels

Side Wall Absorbing Panels

Absorption Or Diffusion

Ceiling reflections can be treated using diffusion or absorption technologies. Each treatment has its own certain acoustic presentation, so you must decide what is the room’s use and what are you trying to do with music within the room. If it is a control room, everything must be heard within the mix and less room sound during monitoring is usually desired. Absorption technology, including low frequency technology, is generally used and located upon the ceiling to minimize ceiling reflection distortions. If your room is for music playback and listening enjoyment then a different room acoustic treatment is needed on room boundary surfaces.

5. Room Size And Volume Critical

Our fifth myth is that you can locate your new music room in any room size that you currently have available. Sorry, we see a lot of this and there are simply some room sizes that have a certain width, height, and length dimension that you can not use because the real, low frequency energy, < 100 Hz., can not be managed at all by current room acoustic product technologies no matter how good they work. In certain room volumes and dimensions, there is no treatment for the low end disease. Find another room size. Sometimes, only a foot here or there will make the difference. Middle and high frequencies also require minimum room distances to be completely heard without room distortions.

The Top 5 Room Acoustic Problems You Are Facing In Your Studio

It’s critical that you manage your low frequency energy, so that you can hear every note from the lowest 30 cycle note on an electric bass to the bass drum attack and decay of each note. Yes, I know it is not easy, but it can be done with the correct technology. Boxes filled with building insulation and foam (bass traps) will not do it.

Room Treatment Balance

Once you have decided upon the use of the room, treat all room boundary reflections, so that those reflections are working with your room usage and not against you. Lets also choose our room that we are going to work with music in, based upon the needs of the music and not any of our human wants or desires. Your music room is not a living room. It is a room to make music in. Choose the room size and volume that gives you a good chance by adding the correct treatment technologies, to achieve a room sound that is energy balanced across the audio spectrum. Sometimes a few feet in just one dimension can make all the difference.

In Summary

So I hope that helps you resolve the room acoustic problems you are facing. If you have any questions at any time I am always on hand to help answer them. Leave them in the comments section or email me at info@acousticfields.com. If you would like to learn more about room acoustics please sign up for my free videos and ebook by joining the mailing list here. I send room tuning tips and things for you to test in your room every Wednesday. They are easy to follow and really help you enjoy more of your music.


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Dennis Foley

I am an acoustic engineer with over 30 years’ experience in the business. My technology has been used in Electric Lady Land Studios, Sony Music of New York, Cello Music and Films founded by Mark Levinson, and Saltmines Studios in Mesa, Arizona, along with hundreds of others.

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