I would do a factory rest and make sure it isnt set to 4ohm in the menu. This limits current and wont help your bass situation. Re-Run your speaker audyssey EQ auto setup.
The left channel is loading your corridor. Not sure where you sit, but Im sure the folks here can help you out if you post a sketch of your room. I see issues that will cause your problem.... like excess treble from lack of furnishings. Chasing bass with volume will continue to flood the room with harsh treble and load the corridor.
Definitely issues with too many hard surfaces and layout.
