Things I learned making my enclosure:
- Drywall at least the interior walls (Plywood doesn’t deaden sound.) If you can get the stuff that is specifically for sound absorption.
- Put the S5 on a piece of plywood that is sitting on EVA foam and not attached to the rest of the enclosure. This decouples the machine from the enclosure.
- Seal all cracks
- Use Rockwool Safe & Sound insulation inside the walls
- Acoustic foam panels inside cut down on the highs
- Get a Spindle
- Get a Stealth Sonic Vacuum
- Make triple layer windows out of polycarbonate and EVA foam. (PC ↔ Foam ↔ PC ↔ Foam ↔ PC). The two air gaps will deaden vibrations.
- If using an air cooled spindle, add a snaking vent passage for heat to escape but not sound. Line it with carpet.
Unfortunately the windows will be the place where the most sound gets through.