amplifier imbalance

[Bushbaby]

Apologies, and I will endeavour to clarify. The speakers etc have not been moved and the system is still sitting as placed. The bass level appears to have dropped as has the midrange and treble has very much increased. No change to any of the output controls, the bass and treble are still set at 12 o'clock (neutral) on the amp. Where I have had the amp at about 50% volume which I had been using over the last week or so, the output is almost painful on the treble side (which I may have wrongly called 'aggressive') to listen to and I've had to turn the volume down.
I am aware that the room is not set up well for a hifi system but Angie and agreed that we wouldn't be putting up any thick curtains but blinds will be fitted. The floor will be left as is with no rugs etc. and we will have to live with this. However, the current change in sound is different from as it was a few days ago so I am wondering if anything has become faulty??

Best Regards