I have owned 3 external dac's and I never gotten any Clipping or bering compressed issues when I ran a DG/DGX, XFI or Omni into them. I always ran them with 100% with out those problems you mention.As I would had notice if the omni was doing the compressing effect with SBX or with it.
When you downmix a 5.1 signal to stereo, you have to attenuate the signal or else it might clip when all the channels are summed together.
As long as all the channels are below a certain volume, they will mix together without clipping.
What I tested was playing 6 channels of 0 dBFS tones (100% volume) to see how SBX Pro Studio Surround handled it.
It seems to be applying some sort of dynamic volume adjustment to prevent the signal clipping.
Reducing the volume of the 5.1 device (not the S/PDIF output) to 70% allows the channels to be mixed together without clipping or triggering this dynamic volume adjustment, even if all six channels reach 0 dBFS.
I agree with 33%. But as for not going above 67%, I don't think I can agree on that anymore. I've had the ZxR for over a year now and I've always thought that going above 67% made no sense. It does when you have a closed headphone, there's no 2 roads about this. Numbers may show otherwise and obviously, not everyone will agree irregardless.
Interesting on that point of not going above 70% on volume though. I do seem to remember clipping on a couple of headphones at some rather high volume, will have to re-investigate this again. But thanks for bringing this up as I've forgotten about this potential issue.
My recommendation was to stay in the range of 33-67%, not to go above it. I generally leave it set to 33% for all content now.
I found my self going crazy about the settings, I'm not sure what to use for gaming / movies / music
I have DT990 600 Ohms, I don't want EQ because we have Crystalizer which does the same just auto.
But I find myself stuck with the Surround and Crystalizer % , and should I or should I not enable Dialog Plus, cause it is auto enabled when using specific profiles, for example Driving simulation.
Last posts someone said Surround 33% is the best, and someone else said 60%, and someone else said 55%.
everything seems to sound fine, but I can't find the pitch perfect to really enjoy the sound, I want to have "studio" surround like I get the sound from the headphones, if we can call it like that, hard to explain
In the Speakers/Headphones tab, set the output to Headphones.
In the Windows Control Panel, check that the Sound Blaster device is set to 5.1 channels.
In the SBX Pro Studio tab, only enable Surround. Choose a setting between 33-67% that you like. 33% will be the most directional. Higher settings blend the channels together more and add more reverb. It's really just personal preference though.
I wouldn't use any of the other signal processing/EQ.