X-over realized by Laptop, Open Source and 7.1 AV Receiver over Display Port / HDMI

Works now, thanks. Good instruction!

Now I just have to check if all the software you are using is available on ARM architecture, so we can set something like this up with a low power Raspberry Pi, for example (think fanless and headless).

I remember Charlie Laub doing something similar with LADSPA plugins:

If I recall correctly, he had trouble getting multichannel audio out of the RPI HDMI port, so had to use an external USB sound card. That was prior to the RPI v3, so maybe things have changed with the new model.