I'm being asked to sit in with a group on Saturday night and they've given me a list of songs they intend to play. (It's kind of roots-rock from the mid-50s through the mid-60s.) In listening to the originals, I hear at least three very distinct bass sounds: upright on some; P bass type sound on some; and aggressive J bass (in fact, I know they were various brands) on some.
If I show up with one bass, I won't be able to cover all three kinds of sounds. I'd rather show up with three basses, since I understand that my role is to cover these sounds, which won't be possible with any one bass.
If they later tell me just play one, so I'm not switching, that's fine too. But I like to be prepared.
Unless the whole band, instrumentally and vocally, is going to nail the sound of the originals does it really matter? Will anyone in the audience say "Hey, only the bass tone sounds like the original song...."
