One of the simplest ways is to put a pillow or blanket into the bass drum.
By the amount and placement of the padding, you can reduce the boom
considerably. There are many other muffling methods available including drum
heads with built-in muffling for a "cleaner" look, however. See your local
authorized Pearl dealer for his or her recommendations.
Visit your local drum store and look for these products: 1) Locking nuts
(finger tightened nuts that thread on the tension rods and counter-lock
against the swivel nuts); or 2) Lug Locks (nylon widgets that press onto the
tops of tension rods to prevent them from turning.
Play on a carpet or rug. Remnants can be purchased from carpet or home
improvement stores at reasonable prices. For maximum slip-resistance, use the
spikes on your bass drum spurs, pedal and hi-hat stand.