Sonic Defender
Headphoneus Supremus
ive noticed more than just louder.like for instance i was listening to led zeppelin stairway to heaven and page solo was a bit sharper and most recognizable to me was bonham's drumming that leads out of the solo hit much harder.so far i have only found a difference with the stronger points of songs like solos,base lines are a tad bit more recognizable,and when the drummer really is getting on the drums hard. To me things like that are what i have noticed.i set spotify at the exact time the solo started as well as tidal.i would listen to one until solo was over and then the other.i did notice a difference. Its hard to tell throughout a whole song but bits and pieces sood out when i compared them. I have a lot more music to compare but so far im not sure if its worth another $120 a year.
Try having somebody help you, set everything up so that volume levels are matched really closely. Then do multiple trials blind listening. See if the differences remain so clear. If something is very subtle with sighted listening, it likely will disappear when listening blind. Worth testing, but the volume has to match very, very closely.