That really fundamental difference between a speaker as sound producer, that is part of a musical instrument and a speaker as reproducer, a PA speaker, studio monitor or hifi speaker. Very different animals. Best bass amp I ever owned in the early 1970s was an Ampeg B15 with a small sealed enclosure with a D130 guitar speaker and tube amp. I've never heard a bass amp since that sounded as good since then. Not an amp I'd ever want to play a track thru tho.