Reducing Noise

Week 4: Reducing Noise -- Demonstrate how to reduce unwanted electrical and acoustical noise when recording.

It may be common sense, but avoiding noise during music production is of high priority. Most of the time you will want to make recordings in which only the instrument or the vocals can be heard. If you happen to be somewhere where the acoustics of the environment are worth recording (e.g. grand reverberations of a church, woodnotes and birdsongs of a forest), you should take care of recording it well -- otherwise, you'll want to get rid of echoes and background noises.

During pre-production you should make preparations, because with a few simple steps you can set up such a system which you can keep your recordings nice and clean with. First of all: turn every disturbing appliances off (such as television or air conditioner), be quiet and listen. Once you get used to the silence, you will find some quieter noise sources which can still be disturbing during a recording (fans of your computer, fridge in the kitchen, dogs barking outside, clocks ticking etc.). Move away from them if you can, or isolate the space which you are recording in. Turn the cooling of your computer down a bit (or clean the fans from dust), or even take it to another room; close the door to keep the noises of your household out; close the window, or simply choose a period of time when your neighbourhood is quite silent and you won't disturb them either (e.g. during working hours).

After you've taken care of acoustic noises, you also should take care of electrical ones. If you have the chance, use high quality equipment. Appliances and instruments of global brands are more expensive, but they tend to be of better quality and reliability. Shielded cables, reliable plugs and sockets, not the cheapest power supply units -- all these things can keep you away from electrical noise. There are less financially demanding methods as well: the shorter cables and the fewer pieces of gear you use, the less electrical noise you will find in your recordings. Turn off the dimmers and appliances you do not use, and use balanced cables wherever you can. Also try to avoid ground loop, which generates a disturbing hum of 50 or 60Hz (it depends on the power line frequency in your country).

After having your recording environment arranged carefully, you can start the production stage. If you happen to have a number of different types of microphones, you should consider using a directional one to isolate the instrument or vocalist from the environment. Directing a cardioid mic to the instrument and moving her closer to the sound source are excellent ways to have more direct sound and less background noise in your recordings. By this way you can also keep the signal level quite high, so you can keep the gain on a moderate level and thus keep electrical and background noises low.

During post-production you still have the chance to fix some noise issues, but you'll want to avoid that as much as you can, as they tend to be destructive or they consume way more time than proper preparations. Using a noise gate can keep background noises out, but by this way you'll lose all the lovely nuances such as the sound of the fingers sliding on the strings of an instrument. A long note fading out can also dissolve slowly in noise, and a gate can't do anything to save it. There are restoration effects such as de-noisers or de-hissers, but the processed audio does not sound perfect at all, since it loses its original timbre during the heavy filtering of the process. Prevention is better than cure.