In article ,
Ignoramus3477 wrote:

Could just an intake muffler and oil bath filter make that much of a
difference? Or does a belt guard add that much to noise?

The intake muffler certainly could. A large part of compressor noise is
from the intake - one of several reasons that plumbing the intake to the
outside is often a good idea (though muffling it is probably _also_ a
good idea if doing that in a residential neighborhood.)

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