Unfortunately there is no volume control for the Orchestrion, meaning it tends to be drowned out by furniture sound effects (like running water from fountains) so you might want to look into removing those if you're having trouble hearing Orchestrion playback. Because the audio from the Orchestrion is directional, emulating an actual hifi system, where exactly you place it in the room can also greatly affect how well it's heard (and how well you can hear it as you move your character/viewpoint around).

So it may require a bit of trial and error moving the Orchestrion and also adjusting other furniture/walls etc in the room to find the 'sweet spot' for maximum audio fidelity (they actually greatly improved the range and audio quality of the Orchestrion from when it was first added - then you basically had to be right next to it to hear it even remotely well).