You actually can slow down music. A novel experience in itself. When you try to learn the song — once you get a grip – everything slows. That's why people play so much with metronome – once your brain "slows down", you will speed up naturally. Spent a few months learning how to get around it as a novice drummer. The only way around I found? It's to notice the slowing speed of time and slow the rhythm into it. Probably related: most drummers play with a click in their ears.

I noticed similar effects when "locking in" in games or sports. Time gets slower.

So when you slow down, you start to pay more attention. But if you pay more attention, the world itself will slow down. And the music would be slowed