3
- You can't connect two sound-sources to a single speakers using Y-cable (might even damage player), instead switch or mixer is need.
4
- Switches cheaper, but mixer is more convinient. Also no zigbee switch available.
5
- Mixers are relatively expensive (reputable brands: behringer, Rolls). The cheap chinese DIY devices dampen and distort sound (ok for talk, but not for music)
6
- Raspberry Pi can do mixing, but we need:
7
* Stereo line-in (via USB cards), - standard mic on usb audiocards is mono. Linux systems however can be linked via pulseaudio server wihtout going analog.
8
* This leaves bluetooth connection. To use bt2jack we would need again stereo-line-in (and going via analog is suboptimal), alternative is an extra bluetooth
9
adapter for receiving audio via A2DP profile (configuration required): bt 5 (not only ble) supported in debian 8.