what musical instruments were played in the background of this track?
Bass guitar, drums, piano
Earth Angel
. It was recorded on a single-track Ampex tape recorder, owned by big band veteran Ted Brinson, who performs bass guitar on the track. The drums were muffled with pillows so as to not overwhelm the vocals. A neighbor's pet dog stopped many takes by barking. "Everytime the dog barked next door, I'd have to go out and shut him up, and then we'd do another take," remembered Williams. Williams performs piano on the track, with Preston Epps on bongos (though this unconfirmed), as well as an unknown drummer. 
who sang the original version of earth angel American doo-wop group the Penguins who wrote the lyrics? Williams, Gaynel Hodge and Jesse Belvin
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Earth Angel [SEP] Background
The drums were muffled with pillows so as to not overwhelm the vocals. A neighbor's pet dog stopped many takes by barking. "Everytime the dog barked next door, I'd have to go out and shut him up, and then we'd do another take," remembered Williams. Williams performs piano on the track, with Preston Epps on bongos (though this unconfirmed), as well as an unknown drummer. The song is composed in the key of A-flat major and is set in time signature of common time with a tempo of 76 beats per minute. Duncan's vocal range spans from F to G.