[linux-audio-user] Strange RME HDSP9652+RME ADI8-Pro behaviour

[Michele Spinolo]

Just to make some tests I looped RME ADI-8 Pro input and output, connected
to a RME HDSP9652 (set as master), and I made some measurements:

http://michelespinolo.altervista.org/rme/meas-chain.pdf

this is the looped set-up with hdspmixer (i.e. total mix) at default volume.

Here the same is done:

http://michelespinolo.altervista.org/rme/meas-chain-gain.pdf

but some gain is given on input channel (no analog or digital clipping
occured).

The results in the latter case are a lot worse than first one, but I do not
know why.
My set-up use a Athlon XP 2500+ (Barton core) Asus A7N8X-X motherboard,
Fedora Core 3 (PlanetCCRMA distro), ALSA 1.0.9a.

Anyone has some idea why this occurs?

Thank you very much!
Michele