Background noise

I am new to Audacity on my own computer and having some problems when recording speech.

I have my mics through a Peavey PV6 USB into the USB port on my laptop running Windows 8.1.

I keep getting background noise, like a high pitched whistle when recording - even with nothing attached to the PVC6, just the USB cable between the device and the laptop. This is even more noticeable when normalising the sound.

Any ideas why and how to prevent this?

Possibly mosquito whine which is electrical interference emitted by the computer and/or its power supply [EMI].

Probably the most you can do is turn-up the gain on the mixer and/or get the mic closer to the sound source for a stronger signal-to-noise ratio. (Depending on where the noise is getting-in, turning-up the analog gain may simply make the signal and noise both louder, so try it). And of course, there is a limit to how loud you can go before you get clipping (distortion).

Or, a different computer may emit less power supply noise through the USB power.

If the noise is low-level enough you can try some noise reduction after recording, but there can sometimes be artifacts (side-effects) so noise reduction is one of those things you just have to try.

This is even more noticeable when normalising the sound.

:wink: Of course… Normalization turns-up the volume (assuming your file is not already normalized/maximized or that the peaks don’t already go over 0dBFS.)

This is a little strange because the Peavey doesn’t use the USB system for anything other than connecting sound to the laptop. It has its own power supply. There could be one other problem. Do you get the Peavey -21 and 0 sound meter green lights to come on when you record? I bet you don’t. I bet you’re making a very, very low recording and it’s the same volume as the very low digital whine that apparently most USB audio devices have. When you amplify your voice in Audacity, it amplifies the whine right along with it. You shouldn’t need amplification if you’re recording at the right level.

I expect at least the -6 Audacity sound meter lights to come on when you record. Do you get them?


What kind of microphones do you have? I did a recent experiment with my Peavey and an SM58 rock band microphone. I got hum and buzz when I got the microphone or the microphone cable too close to the Peavey power supply or the power cable on the back of the mixer. Most mixers and sound equipment runs from a DC power supply, not his one. Yours is 15 VAC at half-amp. Mine is slightly lower. So keep the microphone cables and the power supply system apart from each other.


Are you an old hand at recording? Using a “real” sound mixer isn’t as simple as plugging in a USB microphone.