Brian wrote:

1. Does anyone know of any clubs/bars/venues that currently have PA
systems with at least discrete front and rear channels or any live
sound rental companies offering this type of setup? (generally
curious, but Northeast US and electronic music would the most
interesting). Does anyone ever see this becoming a trend?

I know of a lot of venues that offer this sort of system, and they are
all halls that are also used for showing movies as well as live
performances. Cinema theatres will tend to have at least a single
rear channel if not split rear channels. And there is no reason not
to use the cinema surround channels if that's the effect you want.

Any rental company should be able to configure you a system with rear
channels. If you can live with rear channels that have more restricted
LF than the mains (which should be the normal state of affairs), it
shouldn't be a big deal. Most of them will not have a console with
surround panning, however, so you will probably need postfade aux busses
for the surround channel or channels.

2. I'm going to go with a four channel setup regardless because I'm
recording my sets to a laptop which will always be surround and then
giving the house a downmix. I've been researching and so far it looks
like the best way I can find in something compact and portable is
getting a pair of Rane SM82 rack mount line mixers and splitting my
outputs from my gear so I can use one mixer for the front channels and
one for the back to mix on the fly. So far this mixer seems like the
best since it has stereo channels with balance control and a stereo aux
send per channel. Any other ideas on how to get this kind of control
for four channels?

Use two of them and use the pans for right/left and adjust the gains by
hand for front-back. If you want real front/back panning you're going to
be in a much higher price bracket although Calrec and API can probably
make you something that will fit into a small rack.

3. Finally, I've seen surround headphones but haven't tried any yet.
Is the image from these enough to actually use for live surround mixing
and also are there any that can take a discrete four channel input as
opposed to the ones I've seen that only take encoded two channel?

Why do you need anything other than mono headphones for live surround
mixing? You can hear the surround sound in the hall... only thing you
need headphones for is to check individual channels here and there.
Honestly, mixing a live show, when was the last time you ever cared that
your headphone feed was in stereo?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."