My very first 'live' concert was in about 1955, (I was aged 15) The Ken Colyer Jazzmen. Was a bit late arriving, so held outside the hall, until the first tune came to an end. It was, even outside the hall, loud! When I went in to claim my seat, there was the usual trad band line up - trumpet, trombone, clarinet, banjo, bass, and drums. No PA at all. Even from half way back in the 400 seater hall it was very very loud!
Today trad band line ups seem to need every instrument miked up (Saw Chris Barber recently) Why? I do not get it!
Classical music ensembles do not seem to need amplification to be heard.