"Pipe to the ear of no tone." Keats
This was a rather musical opus:
"Musical with the song 'The Gods Love Nubia'" AIDA
"'60's quartet member" Mama
"'Smooth Operator' singer" SADE
"Any Abba singer" SWEDE
"Relating to pitch" Tonal
"Key with four sharps" EMAJ
Too bad for NIBS at 27-down we didn't get "Her ____, Miss Georgia Gibbs." She was a '50's singer before rock 'n' roll, and that was her intro.
I liked "It can pick up a plane" for RADAR. :)