How do you get rid of the "white noise" on recordings?

[crkt246]

Hi guy I want to know how to get rid of the white noise that I get when I record through my computer.
I use the recording software "Audacity".

[jeffster1]

Does it only happen through your computer? You may need a better sound card.

You could also try a noise gate, but if it's only through your PC it's probably the sound card.

[Ricochet]

Often there's ambient noise that you've "tuned out" and don't hear while you're doing it but notice later on the recording. Pays to take a conscious, deliberate listen to the room before you start. Computers generally make noise from hard drives and fans.

[gnease]

I don't know if anything is offered for Audacity. But I've used Cool Edit Pro II's (now Adobe Audition) noise reduction algorithms on some recordings digitized from cassette and low SNR sources. The scans the file to analyze it for "desired" info (music, voice) based on some frequency, power and other paramters (performs an autocorrelation). In the second step, it uses the gathered info to separate noise and desired audio. What I've learned is that there is no real magic bullet to remove noise. If I try to get too aggressive in removing noise -- more than only a few dB of reduction, the process clearly introduces annoying artifacts in the desired audio. I've learned not to expect too much from such a process. It's probably good for increasing intelligibility of voice at the expense of fidelity (spy-versus-spy or CSI magic), but is hard on the music.

The other thing that might be possible is companding of the signal. However, this will also change the nature of the desired signal somewhat by compressing the higher level signals -- the desired music -- and expanding signals below a certain threshold so they are lowered further in level - hopefully the noise. Does Audacity have a user configurable compander or similar non-linear dynamic processor?

[greybeard]

The first thing to check is whether the noise always appears or whether you only get it when recording electric guitar or mic'ed voice/guitar.
If it always appears, you have to consider the computer to be the culprit. As has already been said, the chances are it's your sound card. I did have some moderate success, with one particular card, by moving it as far away from everything else as I could. Try muting all your inputs and record a few seconds, in Audacity. It will give you an idea of the basic noise level of the card. You could try switching one input, at a time, back on. See how the various channels affect the noise level

If the card is not producing the noise, it's obviously the environment that the computer is in. Set up your mic and record a few seconds of the environment ("silence"). Then, put your mic in a drawer or between 2 pillows and record a few seconds more. The second sample will remove most, if not all, of the environmental sounds. It will give you a good idea of how much the environment is contributing and how much is from the mic, itself.

[Nick]

You should just tell Kevin Federline to go home and take care of his kids...

[gnease]

of course, as suggested by others, you should try to eliminate the noise at the source first. if you are recording using the built-in mic or the low cost electret mic often included with PC systems, it's close to hopeless. you will need to get a better mic and get it away from the PC. and as noted above, many sound cards/on-board sound systems are not than great in terms of SNR performance.

[Chris C]

+1 to it being a difficult task if you have low grade gear.

Eliminating all unwanted noise can become a pretty much endless chase after the holy grail of signal purity. From my own experience (as an amateur) it seems that every single link in the chain can contribute some kind of hiss, crackle or hum. The usual supects include the quality of your house power supply, poorly shielded cables (which can pick up noise from all the other electrical activity), crummy sound cards, cheap microphones, amps, pedals, bad connections and contacts, etc etc. The computer itself can be contributing noise in a variety of ways too.

For instance, I've just been hooking up a system to record with, and working through some of the same issues. When I hooked up the keyboard I was getting a lot of noise from it into the mixer. Changing cables didn't help. But there was also a USB cable attached to the keyboard that's used when the keyboard acts as a midi controller. When it's being used to either provide midi input, or play it back, that cable works just fine, and doesn't seem to contribute any hum. But when the keyboard is providing audio through the output socket then, even though the midi signal is set to 'off' in the keyboard software then the midi cable still completes some sort of unwelcome circuit and transfers noise to the audio. Disconnect the midi cable and the noise on the audio goes away. But then you start noticing the lesser noise that accompanies the note decay from the keyboard..... That's probably going to be unavaoidable with that model keyboard, and fortunately it's not enough to be a problem anyway.

Another difficulty cropped up with the mic. If I plugged it straight into one part of the chain the signal was weak and I had to crank up the setting so high further along that it started to cause hum. That was solved by plugging the mic into another place, where it was getting some sort of 'pre-amp' boost (at least that's how it seemed to me). Anyway, the stronger signal meant that I was able to turn the other setting down to a less cranked level, and that hum went away.

So it's pretty much a process of elimination. If the mic causes problems when plugged into the sound card, then it might work better if the audio was routed through a USB or firewire audio interface, or.... or... or.... there's no one answer unfortunately. Good luck with it all.

Chris

[crkt246]

Aww man looks like its my sound card cause I can plug my tele in and I still got it.

[teleplayer324]

If I remember right, Under effects in Audacity they have a Hiss removal and Pop removal. May not clean it up all the way but it's a start

[Kalle_in_Sweden]

Hi crkt246
What type of Soundcard do you use ?
And how do you connect your sound equipment to the soundcard ?
If it is a standard PC or Laptop soundcard, you should always avoid the mic inputs.
They are always noisy and bad, as they are only designed for use with the mic of a headset and not for recording.
The line-inputs are fairly good as it is easy and low cost to design a good analog amplifier for line levels.
An external analog pre-amplifier or mixer (in front of line-in port of the soundcard) is always much , much better than the mic input amplifier of standard soundcard.
A soundcard for recording purposes (internal or external) has much better analog parts and analog->digital /digital->analog converters than a standard soundcard and a low cost analog mixer
But for a low noise standpoint I would say that a standard soundcard with a good external pre-amplifier/mixer is good enough for most home recording use.
/kalle

[TwistedLefty]

Has anyone tried this?
http://www.youtube.com/watch?v=yOzH71sZ7JE
my PC is contributing a bit more than i want to the mix.
I'm sure that my limited experience (none) in recording is affecting my noise levels, but i defiantly notice a lot of meter action before i start playing.
I'm curious as to weather this would be a simple fix to the problem?
also, a layman's explanation of the pros and cons of using this would be appreciated.
i know building a sound booth is the way to go but that really isn't an option...

here are several methods offered for noise removal, including some free ones that looked a bit more involved.
http://librivox.org/wiki/moin.cgi/NoiseCleaning
comments? recommendations?

[crkt246]

I found my problem and my recordings are so much better.
Thanks everybody!

[hueseph]

TwistedLefty: This is what I posted on the youtube page you linked.

"The problem with this noise removal is that it leaves a lot of artifacting. Basically it takes the sample noise and applies it with the phase reversed. So, anything within the frequency range of the noise will be affected. You can try re sampling the dead space and applying that with the noise removal and "sometimes" it will get rid of the metallic, robotic sound that it created on the first pass. Sometimes. Not always. Listen the the quality of the recording and ask why.........?"

What I meant to say was. Listen to the crap quality of the recording of the "tip" and you have to wonder why this guy is giving tips. Yes the noise removal in Audacity works if used sparingly. Otherwise it leaves something to be desired. Don't over do it. Find other ways to eliminate noise first and you should be fine.

[kent_eh]

I found my problem and my recordings are so much better.

For future reference, what did you do to fix it?