Asphalt is used to make pliable mats placed inside doors to muffle street noise.
From the sacbee.com
Her vocal cords had been cut to muffle her bark, and her breath was horrendous.
From the chron.com
Mark Kelner keeps his loft's windows closed to muffle the street noise from below.
From the washingtonpost.com
Gacy would often stick clothing in the victims'mouths to muffle their screams.
From the en.wikipedia.org
Muffle roar of coffee grinder by bodychecking device against front of fridge.
From the timesunion.com
So you'll excuse me if I muffle my deficit-reduction cheerleading this time.
From the time.com
A mother held her hands over a child's ears to muffle the loud rumble of the planes.
From the pe.com
Drum heads with central silver or black dots tend to muffle the overtones even more.
From the en.wikipedia.org
Immediately, when you first put them on you'll notice they muffle out sound very well.
From the techcrunch.com
More examples
A kiln with an inner chamber for firing things at a low temperature
Smother: conceal or hide; "smother a yawn"; "muffle one's anger"; "strangle a yawn"
Deaden (a sound or noise), especially by wrapping
(muffled) dull: being or made softer or less loud or clear; "the dull boom of distant breaking waves"; "muffled drums"; "the muffled noises of the street"; "muted trumpets"
(muffled) wrapped up especially for protection or secrecy; "children muffled almost to the eyebrows"
A muffle furnace (sometimes, retort furnace) in historical usage is a furnace in which the subject material is isolated from the fuel and all of the products of combustion including gases and flying ash. ...
Anything that mutes or deadens sound; A warm piece of clothing for the hands; A kiln or furnace, often electric, with no direct flames; To wrap up (a person, face etc. ...
(Muffled) Sounds like it is covered with a blanket. Weak highs or weak upper mids.
(MUFFLES) Wax ear plugs. Less comfortable than the foam ones but more effective. From most chemists.