I recently purchaced a “Volumio supported GPIO header solution (I2S) DAC” for my new Raspberry Pi2 because my AV Receiver was only picking up 48kHz on higher sample rate files via HDMI. After some testing and fiddling around I have come to the conclusion that the sound was far superior (clearer with no noise) through HDMI (ALSA) to my AV Receiver. Even my self-proclaimed tone-deaf wife came through to the lounge and commented that is was better before. Obviously now I am thinking of going back to HDMI, but I still have the same problem 48 kHz ceiling problem???
After some research I found that the Raspberry Pi supports HDMI v1.3a which as far as I believe supports up to 192kHz. I then thought maybe it is the software (Volumio, driver or something) and then found this github.com/raspberrypi/linux/issues/494 which states the ALSA driver to be limited to 48kHz, so I assume this is my problem?
My research therefore brings me to the obvious questions; Is the limitation of ALSA true? If so, are there any plans for Volumio to support a higher sample rate through ASLA/HDMI?