When you buy speakers at a store and don't know how to change anything you can get "shouty bright" speakers. Wayne designed these speakers and did a lot of testing to choose components that work together. If you happened to find them shouty for under $10 he could tell you how to adjust them.If you haven't seen a good high efficiency speaker yet the second question about wanting to listen to a pair is a GREAT question. Most people get this pleasure at "Big Screen, Big Sound" places. Then there are those that like big sound all the time :-). That would be the signature of a nice set of Pi 4's.
Best wishes on your search for demo models.
Grant.