Avid HD interface 8X16 volume difference between sessions in 7.1 and 5.1

[garnoil]

This is very strange, but I am sure someone will have a logical explanation. I have an Avis HD i/0 box 8 in X 16 out (analogue). In Pro-Tools HD 12.8 Ultimate, if I make a session in 7.1 the volume levels of the HD i/o are much louder than if I use a 5.1 outputs but...it is the same i/o box, the same session, and the only difference is whether I use a 7.1 output or a subpath of 5.1. It seems than when Pro-Tools uses the 7.1 output it defaults to a much higher output level, like the 7.1 output is +4bdm and the 5.1 is -10dbm. When I put a test tone in Pro-Tools in the 5.1 outputs, the meter of the interface reads X, when I switch the exact same tone to the 7.1 output the meter in the interface is much, much, higher, I am talking at least 12 db higher. So if I calibrate my studio in 5.1 to play 85dbC with a -20dbfs RMS peak, and then switch the output to 7.1, it is blasting hot and reading much much higher than the 85dbc I calibrated at. This happens just by switching the output from 5.1 to 7.1, in the same Pro-Tools session, same i/o, same Avid HD interface, same everything except the output of the software. Is it possible that the 7.1 output in Pro-Tools is somehow defaulting to a higher level? or may be it is always set to be much higher than the 5.1? This makes no sense to me, and I can not find a reason for this. I should mention that my Avid i/o was originally an 8X8and I installed an expansion card to make it an 8X16 analogue. May be, if the interface 'receives' a signal in the expansion card which is tracks 9 to 16, it somehow defaults to a higher operating level? but...by looking at the meter of the I/O box it is the software that is sending out a much higher level when using a 7.1. ?????
configuration.

[albee1952]

Hmmm, could it be the setting for Pan Law?

[LDS]

Just to double check (it's hard to tell from your description), are you calibrating your system one speaker at a time? Are you saying that when you send a -20dbFS tone to the centre channel and calibration your monitor controller for 85dBc, it then changes levels when you change the output format to 7.1?

[garnoil]

Originally Posted by LDS

Just to double check (it's hard to tell from your description), are you calibrating your system one speaker at a time? Are you saying that when you send a -20dbFS tone to the centre channel and calibration your monitor controller for 85dBc, it then changes levels when you change the output format to 7.1?

Yes, exactly. I calibrate one speaker at 85dbC slow with -20dbfs RMS pink using the 5.1 sub-paths of the main 7.1.2 output of the i/o. Then, if I switch the i/o to the main path which is the 7.1.2 the volume of the pink noise - while it remains at -20dbfs in the Pro-Toos software meters, it becomes very loud in the Avid HS interface box. So when using the 7.1.2 output of the software, somehow the level is getting changed in the output of what Pro-Tools send to the Avid interface. It is like the 5.1 is playing at -10db, and the 7.1.2 is playing at +4dbm or even higher. This must be a bug, and I need to re-set preferences, as this makes no sense. But....how about this theory. If I have a 7.1.2 main output in the i/o, and then I create a sub-path of 5.1 (inside the main 7.1.2 i/o, it is possible that when using the 7.1.2 output the 5.1 is also receiving the signal as it is a sub-path of the 7.1.2? If this is the case, then the signal is doubling in in volume and that would make sense, although it seems strange. I am trying to create a 'main' 7.1.2 i/o for when I work in that format, and I am also creating subpaths in 5.1, stereo, and individual channels (for when I work in 5.1). I am trying to create the widest output path, so that no matter what format I work in, the output will always be present in the speakers. My problem was that Pro-Tools can not remember the 'output' i/o of each session, so if I work in 7.1.2 and then switch to 5.1, I get no sound until I go int the i/o and activate and de-activate outputs and sometimes even fix busses.