Organ stops (8)
I believe the answer is:
earplugs
'organ stops' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'organ stops' is the wordplay.
'organ' becomes 'ear' (the ear is an organ).
'stops' becomes 'plugs' (plug is a kind of stop).
'ear'+'plugs'='EARPLUGS'
Can you help me to learn more?
(Other definitions for earplugs that I've seen before include "Stoppers to keep noise out" , "aids to sleep?" , "noise abatement aids" .)