Studio mics with XLR plugs use differential signalling: the mono signal is transmitted on two lines with opposite polarity. That way, crosstalk and interference is reduced.

If your soundcard line-in records those two lines as two stereo lines, it's still not really a stereo signal, it's a (differential) mono signal.

The proper way to convert it to mono (if your soundcard can't be switched to differential XLR inputs) is to negate one channel and add it to the other channel, that will remove the crosstalk and interferences. If you can't do that, the next best thing is to use just one channel ("my voice did only get recorded on the left channel").

If you want to convert the mono signal to stereo, the proper way is to copy the signal from one channel to two channels, possibly with different factors or delay so that it seems to come from the direction you want it to come.

What you've been doing so far (record both channels as stereo) is the wrong way: The polarity on one channel is inverted, and that will give the wrong directional effect.

That's also the reason that applications that downmix stereo to mono will not pack up any sound: As the polarity is inverted, the signals cancel each other out.

So:

• the only hardware solution is to set your soundcard to accept differential XLR input, if it can, and give you a true mono signal. If that doesn't work:

• all other solitions are really software solutions, properly inverting, downmixing and the upmixing the channels.

Studio mics with XLR plugs use differential signalling: the mono signal is transmitted on two lines with opposite polarity. That way, crosstalk and interference is reduced.

If your soundcard line-in records those two lines as two stereo lines, it's still not really a stereo signal, it's a (differential) mono signal.

The proper way to convert it to mono (if your soundcard can't be switched to differential XLR inputs) is to negate one channel and add it to the other channel, that will remove the crosstalk and interferences. If you can't do that, the next best thing is to use just one channel ("my voice did only get recorded on the left channel").

If you want to convert the mono signal to stereo, the proper way is to copy the signal from one channel to two channels, possibly with different factors or delay so that it seems to come from the direction you want it to come.

What you've been doing so far (record both channels as stereo) is the wrong way: The polarity on one channel is inverted, and that will give the wrong directional effect.

That's also the reason that applications that downmix stereo to mono will not pick up any sound: As the polarity is inverted, the signals cancel each other out.

So:

• the only hardware solution is to set your soundcard to accept differential XLR input, if it can, and give you a true mono signal. If that doesn't work:

• all other solitions are really software solutions, properly inverting, downmixing and then upmixing the channels.