Active speaker levels

Nope, 0dB rulez!

If you have real volume controls (-infinte to 0dB), like on a regular amp, then you’d set the volume to max (=OdB). You control the actual volume from the mixer/controller master volume.

In this case the “volume control” is really a +/- 6dB control, more to adjust for loud/quiet sources. Since you want a signal path that is 0dB average, you don’t want to introduce any boosts at the PA end. Hence leaving both input and master levels on the speakers at 0dB.