Sweet! Though I know nothing about sound hardware. Do you just buy "dumb" speakers and connect them all to the RPi "somehow" (with this soundcard hat, I assume)?

I wonder how hard it would be for me to just open the Marshall, remove the "electronics", put an RPi there and connect the speaker/buttons...

Also I spent a few minutes reading the volumio website and I still don't really get what they bring. How is volumioOS better than just having a Debian on my RPi and playing sound files?