06: Sound Proofing & Acoustic Treatment

In this post I'll go over what Sound-Proofing is, what Acoustic Treatment is, and how to get the best possible results when recording.

Pyramid Foam Acoustic Panels.

There's a difference - Sound-Proofing & Acoustic Treatment

First off, Acoustic Treatment and Sound-Proofing are not the same thing. All sound-proofing is to do with acoustic treatment, but not all acoustic treatment is to do with sound proofing.

Sound-proofing prevents the transmission of sound from one space to another - walls, sealed windows and doors provide sound-proofing.

Open a window and have a listen, then close it and listen again - the difference can be significant. When it comes to recording your podcast, you don't want that loud traffic or neighbour's dog in the background.

Professional studios spend $$$, even $$$$$$ to make a space completely sound-proof by building rooms-within-rooms, having floating floors and suspended ceilings, decoupled walls, heavy solid doors, and double or tripled glazed windows.

Most of us don't have that kind of budget - but there are simple and affordable solutions that can yield good results.

Acoustic treatment affects the properties of sound in a space, such as echo and reverb - hard surfaces reflect sound, soft materials absorb sound, and objects disperse sound.

Think of a tiled bathroom with a lot of hard reflective surfaces - sound echoes around and around... Now think of a carpeted room with couches, chairs, books and stuff hanging on the walls - sound is absorbed and diffused by the soft materials and objects.

Effective acoustic treatment is fairly affordable, and there are commercial products and DIY solutions that can be easily applied.

In the blurry background: A DIY wooden block diffuser.

Sound-Proofing Solutions

Basic Stuff
Close all windows and doors. And close the windows and doors in adjacent rooms. If you can, use a rubber or neoprene seal that can be fitted around the frame of any doors and windows to reduce the amount of sound coming in & going out.

Complex Stuff
• Floors can be "floated" - a secondary floor is built upon the structural floor of the room, and is supported by vibration-dampening materials.

• Ceilings can be suspended - a secondary ceiling is put in place, either hung from the structural ceiling or integrated into de-coupled walls.

• De-coupled walls - secondary walls, with an air gap between them and the structural walls, built of brick/cement block, or heavily insulated.

Acoustic Solutions

Basic Stuff
Carpets, curtains (closed), cushions, wall-hangings and soft furnishings - foam and fabric will absorb sound waves and dampen them to some extent. Having a felt table cloth on the table that your recording equipment is set up on will reduce immediate reflections.

Complex Stuff
• Absorption - whether commercial products like foam panels or DIY panels of rockwool, increasing the amount of sound absorbing materials in a room helps to reduce the amount of echo and reverb.

• Diffusion - having objects and angular surfaces helps to distribute sound waves and thereby weaken them, the more the sound bounces around, the sooner it dissipates. 

Auralex is one of many companies that produce sound-proofing and acoustic treatment products. They also have a very nice PDF that explains these concepts in depth, here's a link.

Various forums and websites also provide guidance for the DIYers out there.

A microphone reflection filter.

Alternatives

There are products for those on a budget or who do not have the luxury of a good space to record in, or those who record on the move in difference spaces in different places.

Aside from good mic technique and positioning, you can use portable booths that will partially isolate the mic from its surroundings, whether its a screen like in the image above, or a foam ball like Kaotica's Eyeball, or a DIY foam box that can be easily taken apart. These are by no-means foolproof, but can improve the recording.

And lastly, there's the good ol' blanket-fort/record under the duvet technique. Just be aware of any rustling of fabrics...

Let's hear it... < incoherent mumbling sounds amidst static noise > ...Well, that's no good.

It's cool, I'll just fix it in the mix...

While there are some amazing audio repair tools available, nothing quite beats good, clean, well recorded audio.

A few minutes of preparation will save hours of tears and gnashing of teeth, and even the recording itself.

Thanks for reading!