I flew on a couple or more Dan Air Comets in the 80's (4B's ?) and apart from being somewhat tatty inside they didn't seem particularly noisy, though whilst taxiing with the engines being so close to the fuselage, the whine of differing power settings was more apparent than with newer aircraft. As to Tridents, I flew on a good many in and out of LHR with BEA, probably all the variants and as the engines were above and behind, the cabin noise was fine. They seemed very modern and futuristic back then.