Subject: Re: recording question (mic vs. line) From: Bob Masta <audio(at)DAQARTA.COM> Date: Sun, 22 Aug 2004 09:52:42 -0400I'm not familiar with the mixer you are using, but I am very surprised at your results. Sound cards as a class are notorious for poor quality on mic inputs, particularly regarding noise. The usual advice is "don't use the built-in Mic input; get a separate mixer". I also note the fact that you report only the far-field mic is having problems. I assume you have tried switching the mics between the different mixer inputs, and the problem follows the mic, not the input. Without further information to go on, I will guess that you have two different types of mics. The far-field is an electret mic that requires a power source. The near-field doesn't require it (either dynamic, or electret with built-in battery, etc). The mixer isn't supplying power to the far-field. Sound cards typically do supply power; they do this through the connection on the stereo connector that would otherwise be for the right channel. (Typically 5 volts.) If you have two identical mics and you haven't tried switching the mics between mixer channels, then I'd guess that the mixer is only supplying power to one the current near-field channel. Hope this helps! On 21 Aug 2004 at 18:40, rif wrote: > I'm doing some speech recognition work, but my background is not in > audio per se, and I'm running into some difficulties. > > I'm interested in recording speech simultaneously through two mics > (one near- and one far-field), so that I can have paired recordings. > My computer soundcard has a mic in, which is mono, and a line in, > which is stereo. My basic plan is to feed both microphones into a > mixer (Behringer MX602A), put out a stereo line-level signal to my > computer, record that, and separate the channels later using sox (this > is all in linux). While this technique works, I find that no matter > how I seem to adjust the gains (in either the mixer or the soundcard), > the quality I get from the far-field mic is much lower than if I > simply plug the far-field mic directly into the mic in on the > soundcard and record that. > > Is what I'm trying to do fundamentally reasonable, or am I always > going to lose a lot of quality boosting a computer mic to line level? > Maybe I need a soundcard with multiple mic inputs, and some relevant > software? I said, my goal is to record from two mics simultaneously in > a way that lets me obtain separate recordings of the same signal, but > I don't want to lose a lot of quality with my setup. Any suggestions > or advice are most appreciated. > Bob Masta audioATdaqartaDOTcom