Electronically Generated Noises
It occurred to me that I had left out one essential topic to the discussion of noise, although this one is not related to your acoustic environment. These are noises you hear as you playback your recordings that you didn’t hear with your ears in your studio.
This type of noise could usually be described as a hum, a buzz, a whine, or a hiss. These are electrically generated noises, and could come from a variety of sources.
A low-pitched hum or buzz usually comes from the 60 Hz AC power line frequency getting into your pre-amp or digital interface. The most common source is a bad cable from your microphone to your pre-amp if you have an external one. Even a good microphone cable lying along side the AC power cable for your computer could possibly transfer some hum into your system. A higher pitched whine usually comes from the computer itself, and could relate to a USB cable from your microphone or digital interface into the computer. This one is a little more tricky to run down and depends heavily on your individual equipment configuration, so I’m unable to offer any more specific advice.
A hissing noise in the background of your recording is usually related to the quality (or lack thereof) of the microphone pre-amp. USB microphones have the pre-amp built in and usually are good enough to not inject much hiss. The hiss problem can also be caused by mis-adjustment of the volume controls in your audio path. If your microphone has a volume control and it is adjusted too low requiring you to turn up the volume on your interface or computer, this can also result in added hiss. This is also very much a function of your particular equipment setup so specific fixes are impossible to deliver from my vantage point, but these suggestions will point you in the right direction.
We’ll revisit these issues when we get into specific equipment setup ideas on a future post.