To reduce background noise from an audio mixer
when you say background noise I assume you mean the inherant noise that electronics produce. the the first thing to do is to make sure that all you input connections are shielded type, you don't need to spend money on gold plated connections, but do buy cables that are made with stranded wire and of decent size, bigger (fatter) is better when it comes to minimizing high frequency losses. Next, calibrate your inputs one at a time with a 1000hz signal that is 0db inn level. You can find this signal online through a search. you can also buy small plug in devices that produce this signal at 0 db (that is Zero Decibles) this is a common reference for "consumer" grade mixers, If you can't or don't want to spend any money on this you can use a signal from any tone generator, and some mixers have them built it. If you don't have any of the former, here is what you can do. turn all you mixer controls to 0 (zero) detent. in other words, flat, no treble, no bass, no midrange. on your inputs there should be input level knobs, these woule be set to thier lowest positionn if using a line input signal. if a microphone that level would be different, but wait on that for a bit. now have all you input knobs (or sliders) at minimum level. Now turn on your amplifer (if your using one) or what ever you monitor the output with. Headphones is a good choice as you can hear everything.
You should hear nothing. (nothing is supposed to in the inputs yet) if you hear noise take note of what it sounds like. turn the sound output level out (if headphones, turn up to a high level) and listen again. is the noise white (hiss) or hum (low freqency) if you have no noise, you have a good mixer and that is what it should be.
No plug in your first input, this is your choice but I would suggest you plug in microphone, now turn it up to the point where you can hear your own voice, you should hear just that, and maybe anything in the backgroud (furnace, tv, etc_) the quieter your environment, the better you can adjust this. Remember you will now need to turn up the input level. If you have meters you should be able to adjust the input to register in the green without turning red, a litlle yellow once in awhle is ok.
If this is quiet and clean you are ready to move on. turn that mic down to zero, but leave the input where you set it.
now plug in a line level source (your tape player,/cd player/ but don't use your computer as a source (yet). without anything playing on your machines you should hear very little noise in your headphones, if you hear a lot of noise you have bad cables.
Now play something through the tape/cd player, what ever and turn up the slider (not the input) this should give you a level,again in the green, with a little yellow, NO RED
once finished with this turn it back down and go to the next input. this time plug in your computer which most likely is coming from the green jack on the back (or front) of your PC/Mac or whatever. computers are very noisy machines, and just being close to one is sometimes enough to cause noise in a high gain system. anyway, plug in your computer and listen, you should hear some noise and I'd be surprized if this wasn't the source of your problem. make sure your volume level on the output of your pc is set to maximum, this will give you an advantage when recording. now turn up the slider on this input and listen for the noise level. good cables are important here and also the price of your computer may be reflected here as well since more expensive machines are better filtered and therefor produce less noise.
play a sound file (windows audio samples are noiseless and clearn) so use them if you can find thiem, look in your music folder for the sample files
You may hear some noise but your mixer is now set up at optimum and should give you nice sound if it is a quality mixer, good luck, Keith
Mar 24, 2011 |
Audio Players & Recorders