Dismal signal from conductor (8)
I believe the answer is:
downbeat
'dismal' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for downbeat that I've seen before include "gesture by conductor" , "Casual" , "Depressed - relaxed" , "Dismal and depressing" , "Conductor is likely to make this movement" .)