🚀 go-pugleaf

"D"  wrote ...
> A background (about 50hz) rumble appears in a sound from
> microphone. Windows XP SP2.

In common use, "rumble" applies to low frequency *random noise*
such as from an air duct or a subway train or from a distant highway.

If you are hearing interference from your power mains (presumably
50Hz if you are posting from Russia), that is called "hum" and it is a
very *constant* tone.

We will assume that you mean that you are hearing interference
from power-line hum.  If it is *rumble*, then it is acoustic and you
should be able to hear it with your ears, no headset, no computer.

> I tried two headsets (which surely are good). The rumble decreases if
> I touch the computer case. I checked the inside of the case, did not
> find any improper contacts. The sound card is Creative sound blaster
> live ct4830. I tried the latest Microsoft and Creative drivers. The
> Creative driver does not output sound from microphone to speakers at
> the same time, but only from a recording from the microphone. How to
> prevent the rumble?

Does it hum when no headset is plugged in?
If so, then there is a problem with the computer or sound card.
If no, then *both* of your headsets have a problem

Does the hum change when you move the headset around
the room?

Does it hum when you try using a differen computer mic?

rcrowley posting from rec.audio.pro