Tempo of the piano in something often broadcast (5)
I believe the answer is:
speed
'tempo' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for speed that I've seen before include "The going rate" , "Rapidity of movement" , "Rate of travel" , "Move quickly (and illegally?)" , "Swiftness" .)