Wayne A. Pflughaupt· Super Moderator
Yeah, it'll work, depending on what you're trying to do with it. Naturally if you're taking front of house measurements, you'll have to keep the other mics muted; otherwise they'll all be feeding a signal to REW via the USB. Might want to keep any other channel you have something plugged into muted as well, in case they're adding residual noise. Direct feeds from backline amps can be noisy, as you probably know...
I assume for "EQing monitors" you want to EQ for feedback, which means the stage mics need to be active. Typically the monitor signal is fed from an Aux send, which is isolated from the main output. But muting the mic channels (again for the purposes of letting the ECM 8000 feed REW) would mute them in the monitors as well; an easy work-around would be to simply pull the main sliders all the way out, all but the ECM 8000's channel.
Naturally, if you intend to use REW as an RTA during a performance, you should probably use a separate sound card...
That can't be accomplished by looping the mixer's XLR output to an XLR input?Note any deficiency in the mic preamp won't be included in the soundcard cal routine...