Problem: Mounting drywall on resilient metal furring does not sufficiently reduce sound and noise transmission.
Cause: Drywall screws that are too long, "short-circuiting" the resilient metal furring.
Solutions:
Remove all screws that are too long and replace with shorter ones. Repair the wall. The greater the number of screws that contact the studs or joists, the poorer the noise reduction will be.