Hi Matthias ! Thanks for your replies !
This setup is getting problematic so I decided to step back from my initial surround setup to a 2-channel one until things get sorted out a bit. Divide et impera so they say ...
First, as you indicated previously I thoroughly checked both AES snakes and are OK -no problems with cabling so far. My ADI-8-QS works as expected as DA when feeding it with (and slaving it to) a CD player in any of it's AES/EBU inputs for example. This is valid for any of it's eight channels driving MSP7 speakers. I checked this using the same above-mentioned 8-channel AES snake using a BOB-32 and using every XLR input to connect the CD player successfully. On each channel-pair I got sound as expected.
But I'm still encountering erratic behaviour with the AES-32 feeding the ADI-8-QS with all the gear synched to Big Ben. What it works as a stand-alone setup it seems doesn't work as expected from the computer due to sync loss somewhere in the line.
I can't manage to get proper sound from the AES-32 with any major Windows app. To start with, running a sound test in dxdiag.exe shows everything OK but sound gets rendered to the right channel only even when TotalMix is clearly showing dxdiag reproducing a stereo signal. All apps, Audition configured with ASIO, MPC, etc, render sound to the right channel only, while again TotalMix shows a proper stereo signal being reproduced.
Before AND after upgrading the AES-32 driver from 188.8.131.52 to 184.108.40.206 (stating a fixed external sync issue) the ADI-8-QS AES digital input LEDs flash oftenly showing sync loss, even when the AES-32 driver property page shows all 8 channels firmly synched to the external Big Ben, to which the ADI-8-QS is obviously synched too -Big Ben shows all devices firmly synched at 192 KHz. This sync loss (whether real or not) is not noticeable while playing back (from QuickTime for example) with a stereo setup and the AES-32 interleaved option OFF, but, IS EXASPERATINGLY real and noticeable (cracks pops etc) with a stereo and/or surround setup and the interleaved option ON (which by the way is neccessary in a sourround setup). I don't know what QuickTime is using to send sound to the card but is obviously something different than anything all the major Windows apps do, because all in all is the only app which is sending audio to all channels in all configurations without any problems -even automatically upsampling to 24/192 when neccessary.
So, rounding things up:
1) synching: do you think the synching problem is in the ADI-8-QS trying to catch up or in the AES-32 outputs (which I'm more inclined to think they are) ? Does an AES-32 externally synched to Big Ben guarantee that all it's outputs will stay put at the rate Big Ben is dictating no matter what the computer apps are attempting to do ?
2) sound: what in the hell can be wrong in the setup/config (and it's obviously system-wide) to be getting sound in the right channel only ? ... this issue annoys me the most. It's obviously something related to Windows/DirectShow/ASIO since QuickTime manages to get sound right.
The computer I'm using is the same I used for the last three years, it's super-stable, meticously cared for, minimal apps, no crap of any kind, dual Xeon workstation with plenty of resources. Before entering RME worked like a charm with a crappy AudioPhile for almost three years never having an issue with DirectShow and/or nothing else. It's tested to the bone.
And the worst part is that I started to get blue screens whenever TotalMix is open, but NEVER when I never opened it even once, and this is valid up to two weeks using QuickTime daily so I'm now almost sure is TotalMix the offending app ... system halt, hardware malfunction, happens sometime after opening TotalMix.
Seriously I think that you have a big mismatch between the analog output levels of the QS and the sensitivity of the connected monitors. I am pretty sure you can easily overload them and have to reduce the volume at the QS for normal operation a lot. Then you get loud pops during power on/off. Reduce the sensitivity of the speakers and let the QS spit out more steam, then not only SNR is improved, but the noise is no longer disturbing too.
The ADI-8-QS is set at +4.2 dBu on all its outputs and my MSP7 speakers are all set to this same +4.2 dBu setting (they have switches on the back), so they are perfectly matched. This is what I first checked so I can reach 0 dBfs without risk.