@yo @aspensmonster Indeed I wouldn't, but copyright is often held by corporate entities, or where this is not directly allowed by law, the exercise of the exclusionary rights which it confers. Do I think that a musician will try to charge me for re-equalising their song at home? It sounds very unlikely. Their label, however; I wouldn't at all be surprised by something like that if it were legally permitted. It could be sold as a bonus.
Generally I think that corpus research has at least some justification on the common good. But that's so hazy that I think we can't draw this distinction successfully in law. Without continued data mining, certain things become either very difficult or impossible: updating spell checking databases, search engines, all kinds of very basic things.