I would be really interested to hear more about your calibration procedure. You offer quite a few presets with the advice that we should choose whichever sounds best. But when you guys are setting up a new device-specific profile, you must have some calibration target to work toward.
I’m using Sennheiser HD650’s through a MOTU UtraLight right now, and I have no idea where that falls in the range of “correct” presets. So for now, I just settled on New York headphones.
Regarding volume control, my observations in Audio MIDI Setup tool shows that the gains are being split between the output of DPSReflector and SoundFlower such that each gets close to the square-root of the requested gain in amplitude, or about half each in dB space. Very peculiar.
I ended up just pushing both to zero dB attenuation, and control the volume at the source, e.g., iTunes. There is some attenuation of the source arising from DPS when its processing is bypassed. I haven’t measured it precisely yet, but it seems in the neighborhood of 3-5 dB.