Measure the area that requires a partial fiberglass acoustic tile with a tape measure or measure the obstacle. Draw the measurement line or shape of the obstacle on the acoustic tile with a dark marker.
Lay the acoustic tile on a flat and level worktable. Clamp the acoustic panel to the work surface with C-clamps, with the waste edge, or obstacle, hanging off the worktable.
Cover the cutting lines with masking tape. If the cutting lines are hard to see, draw them again on top of the tape.
Put on safety glasses, gloves and a dust mask.
Equip a jigsaw or circular saw with high-tooth count, diamond-dusted or carbide blade. Use a circular saw to cut straight lines. If you are cutting curved lines, use a jigsaw. Install a diamond-dusted or carbide hole saw on a power drill if you are cutting a hole for an obstacle.
Align the saw with the cutting line. Turn on the saw or drill and cut along the masking tape lines until you complete the cut. Repeat for fiberglass acoustic tile.
Sand the cut edges lightly with 120-grit sandpaper to remove any roughness.