I’ve been struggling with listening to music with severe high frequency hearing loss in my right ear after acoustic trauma.
In addition to loss of high frequency notes, I also have diplacusis: the right ear perceives sound about half a note too high.
I discovered that using Equalizer APO I can compensate for the high frequency loss pretty well with an equalizer in the right channel. As for the diplacusis, there is a plug-in for Equalizer APO called Discord 3. It is able to do a pitch shift in right channel only. After that I can say that I’m probably back to 90% of my previous music listening enjoyment. Hope this helps someone with unilateral hearing loss.