From SimpsonDan@aol.com Thu Apr 04 11:46:38 2002
Subject:Stereo vs. Mono

Interesting topic. How many giggers on the list use stereo on stage? How many house PA systems are stereo? If the answer to the latter question is few (and I believe it is), then having stereo on stage is both a good and a bad thing. No question it sounds better to us keyboard players. Imaging is better, effects are better, etc.

Two downsides. The first is that you have to lug an extra monitor. By far the most significant is that the keyboard sounds you hear are not what the audience hears. And if you are sending the house a signal that is a stereo-to-mono mix done outside the keyboard (in a keyboard mixer, for example), the sound quality to the house is actually worse than if you used mono patches and send a mono mix to both your own monitor and the house.

Stereo to mono does not equal pure mono. The primary issue is phase cancellation - stereo effects often use phase differences to create the stereo image, and they work great. But when you sum those signals back to mono you don't get a simple mono signal back - you get a mono signal with a bunch of comb filtering. The process of using a stereo patch and then summing it to mono actually changes the sound of the patch on the mono feed (relative to using a mono patch).

Net - the introduction of stereo on the stage with a mono PA actually deteriorates the quality of the PA feed and changes its tone. So it sounds better on stage but worse in the mono PA mix. And that is the sole reason that I never do it.

What do other giggers on the list do? Are your stage monitor and the PA feed both mono? Both stereo? If so, then you have no phase and comb filtering issues.

If you use stereo on stage and send the house a mono mix, how do you deal with the phase cancellation issues and their effect on your tone? Ignore it? Judge that the deterioration in the PA feed is not signficant enough in the overall mix and not worth giving up your stereo mix on stage? Are you even aware of the stereo-to-mono problem? I'm kinda curious.

Dan