I have my community theater company's Behringer Xenyx 2442FX mixer on loan from them in my home. This is a real treat because I've never had extended time with a mixer before. Finally, I'm getting a chance to learn something more about them than just their simplest many-in-two-out "funnel" mode. The Xenyx has eight mono input strips and four stereo input strips. It has four auxiliary sender busses and can assign any input to the Main bus, the Subgroup 1-2 busses, the Subgroup 3-4 busses, or to any combination of busses. The Subgroups can themselves be assigned (right word?) to the left or right channel of the Main bus, or to both. When we do a musical, we use a pre-recorded soundtrack and wireless mikes for the actors. We typically have access to two amplifiers, using one to drive the house speaker, and one to drive the stage monitors. For the house, we want both the soundtrack and the mikes to be amplified. For the monitors, we only want the soundtrack. Our sound tech has achieved this in the past by using the pan control on each input, setting it to center for the soundtrack, and fully to the right for the microphones. That way, both the music and the voices are on the right channel, but only the music is on the left channel. We feed the left channel to the monitor amp, and the right channel to the house amp. This scheme works, but it leaves us reliant on Behringer's electronics expertise to fully separate the mikes out of the mix, and also deprives us of the ability to set the monitor levels indepedently of the house speaker level. After some experimentation, it seems to me that a potentially superior configuration would be to assign the microphones all to Subgroups 1-2, and assign the soundtrack to Subgroups 1-2 and 3-4, then assign Subgroups 1-2 to the right channel of the Main mix, and Subgroups 3-4 to the left channel of the Main mix. This again has both mikes and soundtrack on the right channel, for the house, but only soundtrack on the left channel, for the monitors. With this setup, I can set the house and monitor levels independently, by adjusting the Subgroup masters (1-2 for the house, 3-4 for the monitors). Now, I could just use the Subgroup outputs off the back of the mixer directly, and skip the part where I assign them to either side of the Main mix. But, that would mean my stereo sound track would be delivered in stereo to the amplifiers, which I don't want. For amplifiers that have a "mono" button, that's not a problem. But, not all of them do have that button and, for some, it appears that feature is buried in a complicated user-interface I won't always understand. To get around this issue in the past, we've fed our stereo soundtrack into two input strips and just made each channel part of the mix. That, however, wastes an input we'd rather have open for another mike. So, I'd prefer to feed stereo into a stereo input, and "mix" the channels by assigning both Subgroups in a given pair to the same Main bus output channel. (That is, when I feed stereo into a stereo input, and assign that input to Subgroups 1-2, the left channel of my input appears on Subgroup 1, and the right channel is on Subgroup 2. To mix them down to mono, I assign both Subgroup 1 and Subgroup 2 to the right channel of the Main mix, which then goes on to feed the house speaker in mono.) Given that there are four auxiliary senders, two of which can be set to operate pre-fader, I can see there are other ways to do what I'm trying to accomplish. The monitor amp could be fed from one of the auxiliaries, for example. So, I'm looking for advice on good configurations for using this kind of mixer to accept a stereo soundtrack in, along with several wireless mikes, in order to drive two amplifiers, each in mono, one with soundtrack-plus-mikes, one with just soundtrack. All suggestions are gratefully received.