Hi Guys
Many thanks for your responses to date. House amps are Yamaha XP3500's and as I previously indicated are normally run with the gains fully open. I have worked in this particular theatre on and off for about 10 years, firstly with a Yamaha DM1000 and latterly with a Presonus 24.4.2 and have always just hooked the desks up to the main house L and R returns, ran the respective main output fader at unity level and achieved an ideal sound pressure level in the auditorium. (Amps are installed in a remote room and never before have I had to make any adjustment to them. House techs confirm that the gains have not been altered since my last visit so all should be "as normal").
Today I go in with the new M32, set the individual channel input trims to hit about -6 on the meter and start to push up the main output fader and hey presto we get the normal sound pressure level when the main fader reaches the -50 mark!
I know that the house amps do have an adjustable input sensitivity but as I have already indicated, it has never been necessary for me to even consider adjusting them in the past so I can only conclude that he M32 outputs a far hotter signal level than either of my previous desks. What I'm basically looking for is some form of digital trim equivalent to the output pot that exists on the main outputs of the Presonus. Any further thoughts or suggestions would be welcome. Meanwhile I'm just working away with the gains on the Yamaha amps reduced by 60%.