Knowing how to give proper acoustic treatment for a home studio consists of three main components: bass traps, acoustic panels and diffusers. However, before we go into each of these component, it is important to be on the same page about what we mean by sound proofing.
Acoustic treatment vs soundproofing
Sound proofing is the act of making sure sound doesn’t escape the room in which the recording is done. It is usually done to reduce the noise disturbance to places outside of the recording room. This is very different from acoustic treatment whose aim is to improve the sound quality of the recording or music within the recording room. The latter main purpose is not about stopping sound from escaping the room.
In the context of this article, we are referring to acoustic treatment rather than sound proofing. However, we are using the latter in the article title as it is a more commonly used term even though the searchers might be referring to acoustic treatment.
When treating the room, we are concern to reduce the echo or reverb such that the music or recording sounds much better and gives us a clearer indication on the true representation of the sound quality.
These are used to absorb the low frequencies, although they can absorb some of the mid and high frequencies as well. That’s why budget home recording rooms are recommended to have at least the bass traps to ensure the quality of their recordings. Most home recording studios forgot about bass traps as the owners only concentrated on foam panels, without knowing they are not effective at low frequency sounds.
The most frequently used types of bass traps are porous absorbers and resonant absorbers.
– Porous absorbers: they are made from a wide range of materials such as acoustic foam, fiberglass, and rockwool. They are the most common type of bass traps available in the market, and have been known to offer excellent broadband absorption, meaning they can absorb sounds across the entire frequency spectrum.
However, porous absorbers only work best at the lowest frequencies when either built very thick, or spaced far off the wall. This, unfortunately, might become a problem for smaller home recording studios.
– Resonant absorbers: consist of Helmholtz Resonators, which absorb bass frequencies through a small port in an air-tight cavity, and Diaphragmatic Absorbers, which neutralize bass frequencies with a vibrating panel or membrane. Diaphragmatic Absorbers are more popular due to the fact that they are easier to design, and they take up less space.
Resonant absorbers are extremely useful at absorbing the lowest frequencies, but not quite effective with those in the mid and high range frequencies. While porous absorbers work best when spaced off the walls, resonant absorbers work best when pressed tightly against the walls.
A combination of porous absorbers and resonant absorbers can be used to achieve the kind of sound you want with your home studio. For instance, having more porous absorbers and only a small proportion of resonant absorbers creates a drier, more clean and studio-like effect to your recordings. On the other hand, having fewer porous absorbers and a large proportion of resonant absorbers creates a more ambient, atmospheric sound.
These are used to absorb the mid and high frequencies. Acoustic panels should be used as supplementary materials to, and not replacements for, bass traps. This is because acoustic panels are ineffective against low frequencies, so they alone will not provide enough acoustic treatment to your home studio.
Some examples of affordable acoustic panel packages are Auralex Designer Series Treatment 112, ATS Wedge Foam Acoustic Panels, and SoundTrax PRO Studio Acoustic Foam.
These are used to scatter the remaining frequencies. Diffusers are a controversial part of acoustic treatment, since some recording artists don’t use them at all, while others use tons of them. A sound diffuser has the shape of a uneven wall but the unevenness is intentional to bound the sound in different direction. Unfortunately, to use them, you need to know a bit of math as it takes some knowledge of angles and such to calculate what is the right way to reflect the sound. Since it is complex to build, you will understand now why commercial diffusers are so expensive.
An alternative to a real diffuser is simply using a curved surface to deflect the sounds. However, this is not the same as diffusing which is more about equal distribution. Nevertheless, it is a cheap alternative that budget home studio owners can consider.
In terms of where to place them, sound diffusers are usually place at the ceiling to kill the echo or at the back of the recording room to control the ‘zing’ in the room. The listeners are usually sited at a distance from the diffusers such that it has the necessary room to work its magic. Too close to the diffusers and the listeners will hear no difference when the sound is produced.
The reason for using sound diffusers rather than fully covering the whole room with foam panels is not to make the room a ‘dead’ room. This term is used to describe the condition whereby the sound has no ‘bounciness’ since all the echos have been absorbed by the foam panels. The end result is a sound quality that sounds very unnatural and even creepy.
Three-in-one acoustic treatment packages
It is possible to purchase bass traps, acoustic panels and diffusers all in one package, which may be useful for beginners who find buying them one by one to be a big hussle. Some great packages are Primacoustic London 12, Auralex Roominators Pro Plus Kit, and Auralex SFS-184 SonoFlat System.