A lot of years ago now in a well attended and rather eclectic acoustic trad tunes session here in Manchester, a guy turned up regularly with a guitar and, hidden away, a set of GBH pipes. He would always do one set of tunes on his pipes. I would always leave the room.

Those pipes in an enclosed space were painful on the ears. Nothing wrong with his playing but they were unpleasantly loud. You could hear him OK at the bar, you could hear him OK in the loo and you could also hear him fine on the other side of the road outside the pub, very loud. Also his pipes were almost (plus or minus half a semitone) one tone flat from normal pitch. No one could join in, not even guitarists with a capo.

All this changed when he turns up with a midi set of pipes and a small battery driven amp.

He could be in tune with everyone else, he could join in with other peoples tunes and others could join in with him. Volume was not a problem. This was a successful incidence of amplified and acoustic instruments.