I appreciate the cautious feedback and will try to convince our sound man to to move over to my unpowered Yamaha MG124CX mixer . He is pretty wedded to the old Sound Tech and in particular the graphic equalizer he uses to tune.
There's nothing wrong with sticking with what you know if you're happy with the outcome.
On that point , is it necessary to have a GE ?
It depends the rest of the signal chain and the environment.
How would we control errant frequencies with the MG12 panned L to the L1Classic and panned R to the L1 model II?
I have found the L1®s require less help to sound great than some other powered loudspeaker systems. I have graphic equalizers and I haven't needed them with the L1®s. Your experience may be different.
A bit more information:
Our sound man's mixer is a Soundtech PC800 . Sorry no actual pic (or manual) as yet as he is still away but we found an old article on the mixer type.
Thanks for the article. There's not a lot of information out there for the Soundtech PC800.
He asks "In principle though it should not matter what the brand of mixer is?? The signal is an unpowered audio mix from a 1/4 inch jack outlet."
Yes, if you can get a line-level (unpowered) audio mix from a 1/4 inch jack outlet that should be fine at the L1® side off things.
My concern is to avoid damage to the mixer by running it without an appropriate load on the powered amplifier outputs.