When I record from from an AUX group (post fader) to the USB the level is always low when I play it back on other devices. This is even though the levels are near unity on the AUX out. I have to set the compressor gain to 16 or 18 db in order to get a decent level. Is there a record level on the USB that I have missed?
Unity is -18dBFS, commercial recordings will have been normalised to 0dBFS. Leave the headroom there when you record for any peaks, and limit + normalise in a DAW before release.
Chris