How can low‑frequency noise from mechanicals in basements be soundproofed effectively?
To handle that low rumble, first cut down on vibration, then keep out the noise from the air. Put your stuff on pads or spring mounts, so it does not vibrate the floor. Seal up any wall or ceiling gaps with caulk or putty. Beef things up by adding drywall and damping stuff. If you can, unhook the ceiling using special channels or clips that block sound. Thick insulation helps. But, adding weight and stopping vibration are key for dealing with bass.