My tiny explanation as to why the library is so slow: Expect some very technical stuff here.
Did you, it's actually faster to use hyperblocks? (I'm just saying, there's no need to use map for the louder and softer blocks) Also, your reverse sound block doesn't take into account mono sounds (sounds with 1 channel), which can be a problem.
Yes it does, but if you're going to be applying a math function on every item of the list, hyperblocks is actually faster. Now, if that math function was different for each item, then map would be better.