Recording tips: Sound treatment

So you’re ready to record some audio for a project — a voiceover, perhaps, or an interview. You have your microphone and your digital recorder or computer interface. What next?

You need to think about how your studio sounds.

Don’t have your own recording studio? Don’t worry – most folks don’t. But with a little work and not too much money, you can create a space in which you can record the human voice effectively.

Here are four tips to creating your own recording space:

1. Find a time and a place where you can have some quiet. Kids, neighbors’ lawnmowers, colleagues’ telephones – all can ruin a good recording. So find a room, or even part of a room, where you can get some quiet time. And arrange to be there whenever it’s most quiet. If you have noisy central air or heating, try turning it off during recording.

2. Try to avoid a tiny room. This may seem counter-intuitive, but a super-small space is going to have worse problems than a bigger room. The trouble is caused by sound waves bouncing off walls, ceilings, floors and each other, creating areas where certain frequencies are enhanced and others are reduced. In layman’s terms, a small space with hard, parallel walls will sound… bad.

3. Absorb some sound. Most people think they need to “sound-proof.” While real studios certainly do this – and they should – you don’t really need sound-proofing, you need sound absorption.

Allow me to explain: True sound-proofing is really about adding mass to  your walls, floors and ceilings. It ain’t cheap. The good news is for most voice-over and podcast-type work, you don’t really need sound-proofing, assuming you can get the kids out of the house or that you can find a spare room in the office away from the water-cooler chatter.

But sound absorption is absolutely necessary for most audio recording. That’s because most of the crap that can seep into your recordings comes not from the direct sound – from source to mic – but from the sound that reflects off the walls, bounces around your corners and THEN back into the mic. Without getting technical on you, that can create all manner of problems, as I said above.  So you need to find some material to absorb at least some of those reflections.

You’ve no doubt heard of foam products like Auralex. I am going to advise that you stay away from them. They cost a lot for the performance they provide.

Instead, make your own sound absorbers using rigid fiberglass. There are plenty of tips around for how to do this, so I won’t go into that now. But call around to insulation supply companies and find a source for Owens Corning 703. Note: This is NOT the pick stuff you lay down on  your attic floor. That stuff will work to a degree. If it’s all you have, throwing a roll of the pink stuff in the corners of your recording room will absorb some sound. But it won’t work particularly well. Rigid fiberglass is much more dense than the fluffy stuff, and therefore it absorbs much more sound. You’ll need to cover it in some kind of thin cloth, because it’ll make your skin scratchy if you handle it.

If you don’t have time for all that, you can find several reputable dealers of pre-made sound absorbers that use OC 703 and similar materials, like Acoustimat, GIK Acoustics and especially  Real Traps. That last company’s website is a treasure trove of acoustics information, provided free regardless of whether you purchase their products. Read up.

4. Get out of the corner. Corners amplify bass frequencies, but they don’t do it in a linear or predictable way. You may find a random note RESONATING while the very next note disappears. So whether you’re recording or listening, get away from the corner and even, if possible, from a wall. Many audio experts say the best listening position is about 1/3 of the way into the long portion of the room.

Happy recording!

Tags: Making music, music for media, music for multimedia, recording audio, recording techniques, sound absorption, sound treatment