Quoted in The Big Beat: Conversations with Rock's Great Drummers (Levon) ↑

The Electric Bass First Started to Come Around

Around this time, the electric bass first started to come around. As soon as that hit, the whole rhythm section changed. With an electric bass, drums, guitar and piano, you had a full group. You had those two electric instruments, and they would sustain that bottom note. Like Scotty Moore, who played guitar with Elvis Presley. He’d be carrying along with his thumb and his pickin’ finger on the bass strings and keeping the whole thing happening with lots of echo and reverb. And with his other fingers he’d be playing the melody. But when he wanted to stop and really bend those strings and make them cry and do what everybody likes to hear an electric guitar do, all of a sudden the bottom fell out. Now, with the electric bass carrying the load you could reach on up and grab your fill and pluck two strings if need be in order to fill that gap. Also, the electric bass caught on pretty quick because you didn’t have to tie that big “doghouse” [stand-up bass] to the top of the car. And all of a sudden you had a guy that wasn’t crippled from trying to play that damned stand-up!

Levon Helm, as quoted in The Big Beat: Conversations with Rock’s Great Drummers