Astra Electric Audio System Failure

That's frustrating. Is there any sign of life at all? Does the screen light up? Can you access any of the menus? Have you tried connecting a phone via Bluetooth or the auxiliary input to see if anything comes through? It's like trying to listen to a symphony with earplugs in if the basic input isn't working.

Screen works, menus are accessible. Bluetooth and aux both silent. Could a speaker issue cause a total system failure?

While it's unusual for a single speaker to cause complete system failure, a short circuit in the bass speaker could potentially overload the amplifier and shut down the entire audio output. It's akin to a single bad apple spoiling the whole bunch. Given that you've eliminated the input sources, I would suggest a visit to a qualified technician for diagnosis and repair.

Workshop confirmed defective bass speaker. Repair cost 280€.