I record in multitrack mode. Instead of configuring all of the outputs for playback, I just simply want to listen to playback (summed channels, mono) through my main LR out. Is this possible?
I’m afraid, I don’t understand the question. You need to rephrase it.
You can switch every input to use the local socket or the USB / SD card input.
It is necessary to configure the recorded channels for playback, otherwise you will still be configured to record. Once you have it configured for playback, save that as a Scene. This can save you some time and effort.
I don’t think the CQ system will handle this as you want. If you record multitracks, you literally have multiple files that must be accounted for. You can play one file at a time I guess, but in order to play all the files at once, you will need to use multiple inputs because the audio is technically coming from multiple sources (ie files).
Of course you can use a DAW to “mix down” the mutlitrack recordings and output a single mono/stereo signal which you then input as a source in the CQ, but that is different than expecting the CQ to handle this internally.
What if I record Main LR as a channel and only want to play that one back? Is that possible?
Yes. You can record the stereo output (Main LR) and that would be easier to playback. Just be aware that the recording is going to match the Main LR feed exactly (good or bad). There is no going back and “correcting” the mix like you can with a multitrack set of recordings. But it is far easier to manage just a stereo recording if your main goal is simple playback.
If you’re recording a band live with the various instruments running to the PA in addition to taking the stage volume into account when mixing for the room, a recording of just L/R is going to sound absolutely horrible and unusable.
Even if you don’t do any editing after the fact, just record all the individual tracks and mix them down using the mixer itself. I’ve already done this a few times. It’s very easy with something like Audacity. You run the mixer into Audacity and set Audacity to record the L/R channels. Then you mix the individual tracks out to L/R at the levels you want them.
It’s a quick and dirty DAW. You can even adjust the EQ for each channel or add effects or whatever directly on the mixer.