What do we know about recording studios? After working on over 1,000 projects during our combined 60 years of experience in the recording and audio business, including key positions at Dolby, Lucasfilm THX, and the famed Record Plant studio, we have developed a bit of insight into the things that really affect your studio’s sound quality, and what you can do to improve them! Check out the top 5:

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1. Clean up your room acoustics

The most important thing you can do is to add an acoustical treatment package. How come? More than 50% of what enters your ears is from sound waves that have bounced around the room surfaces after leaving your speakers! It stands to reason that you should pay some serious attention to those room surfaces.

Acoustical treatments are panels that you hang on the walls and ceiling to effectively control the sound waves that ping-pong around the room. These add-on panels come in various sizes, shapes, and colors, and can even have custom artwork printed on them to match your design aesthetic. They remove the booming echoes that muddle up your work, while retaining the actual character and fidelity of your voices and instruments. You will immediately hear the difference in your recordings and your mixes.

Yes, acoustics may seem like a complicated and confusing art form. But by following simple formulas we derived from engineering hundreds of rooms over the last 30 years, you will get great results:

• Absorption Panels

Absorbers act like sponges for sound waves, sucking up all the energy that hits them. Apply absorbers to about 20% of your wall and ceiling surface area. The absorption material should be at least 2” thick. Spread your absorbers evenly throughout the room. See below for layout recommendations.

• Diffusion

Diffusers scatter sound waves, breaking them up into a smoother soundfield. Apply these scattering modules to another 15-20% of your walls and ceiling. Diffusion should be at least 2” deep (preferably 4-6”) and interleaved with your absorbers. Use 2D diffusion (scatters into a plane) towards the front of the room and 3D diffusion (scatters into a hemisphere) towards the back and on the ceiling. See below for layout recommendations.

• Bass Traps

To control pesky bass buildups and cancellations - known as standing waves - add bass absorption usually in the front or back corners of the room. Bass absorbers are often referred to as “Bass Traps” and should be made of dense fiber or foam material at least 18-24” deep. Models that have a semi-rigid front plate offer improved performance. See below for layout recommendations.

For recommend layouts of these acoustic modules, take a look at this web page: www.sonitususa.com/samplelayouts. Or build your system here: https://www.sonitususa.com/product/studio-acoustical-systems. You’ll notice that the placement of absorbers and diffusers is asymmetrical. That’s because research shows that you get better imaging from mixing it up a bit. Remember to source good quality products - appearance does not always equal performance! For more info, look at their acoustical test reports.

2. Position and aim your speakers

You wouldn’t believe how much the sound of a speaker changes based on its position in the room. Even movements of 6" can have a profound effect, especially in the bass region! Your goal should be to position the speakers to achieve smooth, neutral frequency response, so go ahead and experiment. A good spectrum analyzer with proper test signals will help you get through the process; try https://www.roomeqwizard.com/ along with a simple but effective UMM6 USB test microphone.

For a more precise results, see the section on room EQ below. Some general guidelines are to separate the speakers by a distance that corresponds to 0.83 times your distance to those speakers (this will give you a 45 degree subtended angle). Try to sit at least 10’ feet away from the speakers so that you are hearing the soundfield from the same perspective as your audience.

Place the speakers so that they are least 3’ from any wall or corner. Raise them up over the work surface so that their soundwaves aren’t bouncing off the desk. Aim the speakers at an average of your mix positions so that they sound consistent throughout the area. And please do remember that seating position will also have a profound effect on the sound you hear, so go ahead and experiment with that too!

Note that acoustical treatments will definitely help reduce the effects of placement and widen the listening sweet spot!


3. Use Subwoofers

The position effects we mention above get even more dramatic in the low bass frequencies. Changes of 1' can have a 20 dB effect on the sound at some frequencies. Even if your monitors can play down to 40 Hz and below, chances are that your room will mess with your bass linearity through a process called standing wave resonances. A magic bullet for this issue is to use properly placed subwoofers to carry your bass below 80Hz. You will need a crossover between your monitors and subwoofers so that they integrate properly. That can be implemented in your DAW, or in your subwoofers if they have built-in filters.

Don’t believe the legend that, since bass is omnidirectional, you can place a subwoofer anywhere. Those pesky standing waves will mess you up before you know it. Best thing is to divide and conquer by using multiple smaller subwoofers. Two in the middle of the left and right walls, or middle of the front and back walls will work well.

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For even better results, use four subs in the four corners, fed by the same signal but with the ability to independently adjust levels, delays, and frequency response. A spectrum analyzer scheme will come in handy for this part!

Take a look at this webinar for more than you ever wanted to know about subwoofer locations: https://youtu.be/InwRYDzgEQk

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4. Equalize your speakers

Even after you have acoustically treated your room, you will need to correct the remainder of what the room's acoustical thumbprint is doing to mess up the frequency response of your speakers and allow you to custom-tailor your speakers to your room. That’s ideally accomplished by carefully measuring and analyzing the speakers after moving them around for best results (see above), and setting correction filters in an outboard digital equalizer. The outboard devices can fine-tune the frequency response, levels, and time synchronization in ways not usually available with software plugins. Some people claim that adding an EQ will "pollute" the sound, but that is legend from over 40 years ago. Products made today work incredibly well - we have never noticed any detectability in blind A/B comparisons.

Take a look at these product lines:

‍www.ashly.com

www.minidsp.com

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Note that some of the “robotic” auto-EQ schemes can work, but you should use these as judiciously as you would a microwave oven to prepare a fine meal. It could all come out rubbery and tasteless…. Of course, you should also listen to your favorite program material to make sure it sounds amazing!

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5. Lower your background noise

Music can have a dynamic range of sound up to 120 dB. That means some sounds are very loud while others are very subtle. If you don’t want to miss the small sonic nuances that make up the velvet of the experience, you need to keep the background noise in your room at or below 20 dB (NC). Below 10 dB (NC) is even better but can be very hard to achieve.

A simple test is to plug your ears with your fingers for at least 10 seconds, then unplug and listen. You will suddenly notice all the background noise. Ventilation, heating, and cooling are common culprits, as are refrigerators, plumbing, traffic, wind, and other environmental sources. Bottom line? You need to get rid of all of it to achieve audio nirvana.

You will possibly need to implement sound isolation construction around your room, and isolate the noise sources on springs, rubber pads, etc. To do this right, you’ll want to engage the services of good acoustical professionals (www.pmiltd.com). At the very least, shut off the HVAC and fridge when you are doing your final mixes, and set a timer to remind you to turn the fridge back on before your beer gets warm!

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