Based at RAF Thornhill (5 FTS) in S. Rhodesia 1951 - 1953, individual Harvards were noisy, but we got used to it. However, a formation of 21 flew down to RAF Kumalo for a football final at which Thornhill were playing. So one Harvard can be noisy, but 21 together can be very noisy.
Formation photographed by me at the time.
21 Harvards together