If you remember it from chemistry class, you’ll recall that diffusion is the movement of a substance from a high concentration to a low one. Water and gas follow the properties of diffusion. Sound is the same. Diffusion in audio involves the scattering of sound waves, thus reducing the localization of the sound. If you’re in a completely empty room and speak loudly in it, your voice will bounce off the walls as there’s nothing to deflect, absorb, or diffuse it.
Bouncing noise causes echoes. According to Rupert Brown of DSP Project, “Using a diffuser in your recording room reduces echo and improves the richness of your sound.”
And, even in your house in general, putting up a sound diffuser or two just improves how well you can hear vocals, music, movies, etc in your house.
So, that leads us to the original question: Do you know to properly use a sound diffuser?
Why you should be using a diffuser?
You’re probably reading this because you’re trying to trick out a room in your home and make your own personal recording studio. However, most homes don’t cater to the needs of someone wanting to record high-quality audio.
“If you try to record a song with a guitar and a microphone in your room, you’re audio is going to sound amateur and weak,” says Creative Edge Music.
However, if you make a few adjustments to the listening room, by adding things like bass traps as well as sound diffusers like acoustic diffusers, you can greatly improve your audio by reducing some of the interruptions, frequency response times, and rate of diffusion associated with a bare room.
One such association is the echo. Echoes kill your recording and will make your listener want to turn off the track and listen to something better. Diffusers allow you to reduce echoes in your recording room without making all the time, money, and effort to soundproof your personal studio.
What’s the difference between a diffuser and sound absorption?
Diffusers diffuse sounds. Sound absorbers absorb sound. Both have the purpose of reducing echoes in your recording studio, but both need to be used at different times.
For example, if you’re recording in a room with multiple interworking components in it you’ll want to hear all the parts together to create a richly entwined sound. That room is a kitchen in which you want to cook sounds, and all ingredients must work together.
In the room where you’re processing the sound, such as the mixing room (as recommended by sound engineer Emerson Maningo), you want it to be as quiet as possible since the sounds should no longer mix and mingle.
You’re focused on tweaking the sound as is and changing what you already have. Outside noise will be distracting at this point. Therefore, absorbing your mixing room will be the best bet to reduce extraneous noise and to help you focus on your work.
In your band room, use a diffuser to create richer sounds that build off each other without echoing and sounding messy.
Using a diffuser is more nuanced than you think.
If you think a diffuser is there to just look cool, (which it kinda does), you’re a bit mistaken.
Despite its seemingly random design, the diffuser is an incredibly mathematically precise tool to scatter sound and stop it from bouncing off a wall all at once. Just look at all the math Denis Foley of Acoustic Fields did.
Here’s a Yukon diffuser.
See how deep some blocks of wood are and how shallow others sit in the diffuser? This is where the sound diffusion occurs.
Imagine the sound wave as a wave of water. Sound gets the most power as a single unit, a sheet of noise. When it hits a wall, it keeps all of its integrity and bounces back in the same composition, decreasing in volume but keeping its original tone.
When it’s hit in a diffuser, it acts like a porcupine poking away at that sheet of sound. Some blocks of wood reach the sound before others, which loses its integrity. The sound wave loses its energy and scatters in its weakened state. But these large diffusers made of multiple small blocks of wood, such as the Yukon diffuser, cost a lot and weigh a lot and there are simpler solutions.
That’s a huge diffuser
It’s bulky, too. If that’s not what you’re looking for, there are smaller ones that do a similar job but at a fraction of the cost and weight. Take the ATS Acoustic Diffuser, for example.
This stands much sleeker in a room and isn’t as in-your-face as the Yukon one. Plus, the different depths in the wood paneling ensure similar sound diffusion as the Yukon diffuser (though it won’t be a diffused or scattered).
If you want it for aesthetic reasons, you can’t go wrong with the ATS Acoustic.
If you want to save on cost even more, you can find tutorials on the Internet on how to make your own diffuser, such as on Arqen.com. Getting a diffuser doesn’t have to break the bank.
Where’s the best place to put a diffuser?
While there are lots of places to put the diffuser, you’ll want to use common sense as to where the best place to put it is. Depending on the diffusers size, you’ll want to center it as much as possible to the middle of your wall space. If you put it too far to any side of a wall, you’ll free up bare wall space for sound to echo.
It would also be best to put a diffuser on all four walls in your room. If you have carpet then you shouldn’t need anything further, but if you have tile or hardwood go ahead and get a shaggy rug. They’re like cheap wall diffusers made of fabric.
Just be sure that hanging up your diffuser won’t damage your wall in any way, as having the plaster ripped off will surely affect your sound as you record.
For a more in-depth guide on how to trick out your recording space, check out this article from Arqen Sonic.
Here are the main takeaways:
– Too much absorption causes a flat, unnatural sounding recording space. Diffusion gives you a natural sounding room yet control over your reverb.
– Diffusers preserve the energy of your sound by reflecting sound energy instead of absorbing it. In this way, multiple sounds can work together to create a new unit of noise instead of different sound waves competing against each other to be heard.
– You can even make a small room sound bigger using a diffuser. The ear is designed to pick up on the reverberations of noise, and the more reverberations there are, we assume there is more space for the noise to bounce off of.
– Using a diffuser scatters noise much in the same way a large room does, giving your small room the illusion of a big room. Even if all you have is a closet to record in, you can make your sounds much fuller with a wooden diffuser.
Creating a home studio takes time and dedication—in addition to all the equipment you need to make it as efficient as possible. A diffuser is a must-have for your recording room if you want to keep top-notch sound quality without suffering through echoes.
Use a diffuser to improve the sound of your studio. You won’t regret it.