Older ac units..
My experience with the older units is that they are MUCH QUIETER than most of the new, especially the mid 60s Westinghouses, they used a different set up, the cabinet hung down outside the window so the compressor was actually lower than the window, thus most of the noise was kept outside, we had a Fedders round wheel at home in my bedroom that was about as quiet as a fan running, it had two settings, fan and cool, no thermostat, it was a 52 model, and would get so cold you couldnt stand it!