I am quite surprised with how quiet the California Air Tools compressor is.
How quiet?
The construction-grade Porter Cable compressor is 95dB at 1m above it. Loud. You’d actually require hearing protection if subjected to that for more than a few minutes. You’ll practically need to yell to be heard.

The California Air Tools compressor rates a staggering 62dB when measured at the same position.
You can easily have a casual conversation over it…or even a freaking whisper.