I made an enclosure out of OSB and put corrugated rubber carpet underlay on the inside. The ends were about 15mm longer than the sides to leave a gap for air flow. I don't have a decibel meter, but I don't need ear defenders with the enclosure on but did before the enclosure.
Mine is outside in a underground well with my DX, covered by a ply / metal roof.
A little noise through the air hole but quite quiet in the shed, and sucks the dust out of the garage.
This is my compressor dose wha I want stapler nails a bit of spraying and general cleaning up all most silent and doesn’t lose a pound in pressure when fully charged