acoustical noise, Coursera, electrical noise, home recording, IMPMOOC, Introduction to Music Production, music, noise
This post is submitted for assignment #4 for the Introduction to Music Production course at Coursera.org.
In this post, I will describe the ways I have, with my own setup, encountered acoustical and electrical noise and how I can reduce or eliminate them.
My recording setup is fairly simple, without much sophisticated equipment. I use a Windows laptop to record, using either REAPER or Audacity depending on how complicated the project is. The sound card on the laptop handles sound input poorly, so I use an auxiliary USB sound card (Soundblaster X-Fi) to receive input. The X-Fi has a mini phono jack to receive signals. I run an unbalanced cable (with a male mini phono jack on one end and a male phono jack on the other) to connect an amplifier to the sound card. I connect either a microphone or an instrument (electric guitar or bass guitar) to the amplifier in the input jack. The microphone is a cheap omnidirectional dynamic microphone I got years ago from Radio Shack and badly needs to be upgraded.
I record in an upstairs bedroom that has my equipment but very little furniture. It is a small room, about 18′ long and 12′ wide, with one window. The floor is carpeted but there is a loose floorboard near the door. There is an air conditioning vent in the ceiling. There is a ceiling fan with a light on a dimmer, and two floor lamps that used to have compact fluorescent bulbs until I changed them back to incandescent lights. The room is above my daughters’ bedroom.
I have encountered a number of sources of acoustical noise over time. I have at times picked up the ceiling fan, air blowing from the vents, creaks from the loose floorboard, the sound of the TV on downstairs, my children’s voices downstairs, or my barking dogs.
I use a number of strategies to avoid these acoustical noises. I keep the window closed to avoid outside noise. I keep the fan turned off. I turn off the thermostat to avoid air blowing through the vents. I try not to move around, and I often play seated to avoid the sound of the floor. I try to record when my family is not home or when the children are asleep to avoid them making noise. I will let the dogs out in case they bark. I turn off my cellphone and cordless phones if using a microphone so they won’t be picked up. I keep the door shut to the room. I keep the space I’m working in clear to avoid accidents. I point the amplifier away from the microphone or instrument to avoid feedback.
I have had problems with electrical noises that I have not completely eliminated yet due to equipment limitations. Since my music production is avocational and not professional, I can’t justify making expensive investments in equipment, though I do plan to gradually improve my equipment over time. I have found the fluorescent lights create a lot of noise and had to be replaced by incandescents. The dimmer (and others in the house) must be turned off, because they create noise. (I have experimented with recording by candlelight). There is often a background hum that I have not yet identified, but I believe it is from the cheap microphone; replacing it with a better quality microphone (particularly a directional microphone) will remove some of this noise. Switching to direct input using balanced cables for the guitars will help remove noise from stray radio signals. I may also be picking up a hum from either the laptop itself or from the sound card; I’ll only be able to eliminate that using a noise gate or by using a different recording device. I experienced an alarm-like ringing on a recent recording using my acoustic bass guitar; I have not conclusively found the source of this ringing but I believe it came from the bass amplifier, a Peavey I’ve loved dearly but have used for 25 years, and it is starting to die. I have recently replaced it with a new bass amp but have yet to try it recording. I hope this will help. I am mindful to try and keep the gains down when recording so as not to amplify any electrical or acoustical noises. I may be picking up radio signals from the guitars’ pickups if they are not shielded properly. I could fix the loose board in the floorboard, but I don’t plan on doing that until I replace the carpet in the room. (I have considered using a laminate or hardwood floor, which might add an element of natural reverb but might also amplify acoustical room noise).
I have had some success with removing noise using band pass filters and other filters, but have not yet had the opportunity to try using a noise gate filter. I suspect this will be more effective, given that it attenuates all frequencies that are below a certain volume threshold. (This would not have worked for the ringing bell sound mentioned above, because the noise was fairly loud and comparable to the sound of the guitar itself).
It’s been a challenge learning to improve my recordings and minimize acoustic and electrical noise, but it’s been a worthwhile effort, and I look forward to continuing to improve the quality of the home recordings I create.