My hifiberry DAC+DSP card has starting acting up recently for no reason that I understand. Some info:
The card is installed in a rpi 3b running libreelec. It´s been doing so for almost a year, where the digital input had another raspberry connected to it, and then the analog output was connected to my Onkyo amplifier.
I was using the libreelec rpi to receive streaming from yet another raspberry via airplay, and this all worked well. There´ll probably be somebody asking what the purpose is of this:
The libreelec rpi is used for watching movies, series etc., and the airplaying from another rpi is so that I can play music from spotify to through it, as well as youtube videos. The host for this is a raspberry functioning as a thin client for a Windows machine elsewhere in the house.
The raspberry digitally connected has ubuntu with Reaper, a music making application, to which my midi keyboard is connected. So the libreelec is also used as a bridge for when I want to play my midi keyboard.
Why all this hassle? Because it´s no hassle: It lets me watch movies, listen to spotify and play midi keyboard without ever touching the remote for my amplifier, all at the same time if I desire. It´s an awesome all in one solution.
But since a week ago, the output from movies played via libreelec has become distorted, as well as that of spotify and youtube streamed via airplay. The weird thing is that whatever is sent to the digital input is NOT distorted.
Although the last thing mentioned should prove that nothing is wrong with my amplifier, I decided to connect the output from the problematic pi to another - verfied - input on the amplifier, but the result was the same.
Libreelec has not been updated and I have not changed anything in its settings, so my conclusion is that something must´ve messed up on the hifiberry board. I do have some hopes though, that there´s a way to factory reset the card, or take other steps to resolve the issue. FYI, if I SSL into libreelec, I do not have a volume control with amixer. Libreelec does have volume control that can be accessed remotely, but lowering the volume does not resolve the issue.
Finally, just so you know: Using the rpi with libreelecs sound through HDMI works fine with no distortion.