So my battle weary pair of headphones gave up the ghost and I had to buy a new one.

The new one is better. Everything sounds clearer, including an old suspicion of mine: the headphone/monitor output on my audio interface is quite noticeably louder on the left channel! That always "kind of" bugged me, but now it's too clear and uncomfortable.

I suppose there is nothing I can do but replace the interface... Is there? frown