I've been fiddling with various settings and volume levels using alsamixer-see a screen shot of the features of this card that alsamixer detects at (bear in mind this screenshot is just to demonstrate what alsamixer sees: those settings have been adjusted and readjusted many times, so the current adjustments don't match what's shown in the screenshot). In the latter case, it is much quieter and so more tolerable, though it can still be heard. In the former case, the noise is just too annoying to listen to the recording for any length of time. Oddly, the high-pitched noise is much louder when I record through the rear mic jack than when I record through the front mic jack. The problem I'm having with the sound concerns recording input from the mic: I can record, but there is a high-pitched background noise in the recording on playback, and I've been unable to get rid of it. Playback of, for example music or sound in videos is fine. This machine has HDA Intel SigmaTel STAC9221 A1 sound system, which is generally working. Those factors should be borne in mind in considering the following problem. But I try to avoid a lot of the unnecessary overhead of graphical environments and applications, so many of the standard Ubuntu graphical utilities for looking into sound issues will be absent on this machine. It's a system I built up from scratch from a minimal installation. This issue refers to a highly-customized Ubuntu installation that doesn't use any of the standard GUI stuff.

Intel sigmatel audio