It's a motif similar to the panels used in recording studios to deaden the sound.
From the suntimes.com
So he first puts a little bit of something on your gum to deaden just the surface.
From the telegraph.co.uk
The microscopic holes in woven upholstery fabrics help deaden sound, Gluckman says.
From the kentucky.com
They want the flat's leaseholders to carpet the offending floors to deaden the din.
From the independent.co.uk
Insulating the close-together pipes with foam tubes will deaden the noise.
From the timesunion.com
If that trend continues, it will deaden the possibility of an export-driven recovery.
From the theatlantic.com
Because they deaden the senses, pain medications are the worst way to construct a new map.
From the time.com
In response, the tip of the catheter emitted a blast of radio waves to deaden that spot.
From the ocregister.com
There is carpeting on the floor, walls and ceiling to deaden the sound.
From the courier-journal.com
More examples
Dampen: make vague or obscure or make (an image) less visible; "muffle the message"
Girdle: cut a girdle around so as to kill by interrupting the circulation of water and nutrients; "girdle the plant"
Make vapid or deprive of spirit; "deadened wine"
Lessen the momentum or velocity of; "deaden a ship's headway"
Become lifeless, less lively, intense, or active; lose life, force, or vigor
Convert (metallic mercury) into a grey powder consisting of minute globules, as by shaking with chalk or fatty oil
(deadened) dead: devoid of physical sensation; numb; "his gums were dead from the novocain"; "she felt no discomfort as the dentist drilled her deadened tooth"; "a public desensitized by continuous television coverage of atrocities"
(deadened) made or become less intense; "the deadened pangs of hunger"
(deadening) boring: so lacking in interest as to cause mental weariness; "a boring evening with uninteresting people"; "the deadening effect of some routine tasks"; "a dull play"; "his competent but dull performance"; "a ho-hum speaker who couldn't capture their attention"; "what an irksome task ...