I've gone on lots of auditions, and I've gotten lots of gigs. I agree with @thewildest, as that's been my experience. There is no normal. There's what I'd like to consider "considerate", which would be a week, give or take, but I've gotten gigs long after the audition. And it wasn't always for the reasons I thought, ie. they're looking to see if they can find someone better. More than once a band was settled on having me as their bassist, but wanted to iron out a bunch of other stuff before pulling me in. They were in fact being respectful by getting their stuff more together without putting me through the process with them.
A couple of other times, I auditioned and didn't hear back at all for a couple of months. Either they DID go with someone else and it didn't work out, or they just needed time for reasons unknown.
What I've started to do now when I audition is let go as best I can of the outcome. Move on as though I don't have the gig. If something comes up that seems like it might conflict, I'll check in with the band and tell them I need to know what they're thinking as I'm about to move forward and want to do so with a clear head. I'll wait at least a week before that email.
I'll also trust my judgement. I can tell if I fit with a band or not. If I have any question about whether or not it was a match made in heaven, I'm okay with just moving on. Don't want to sound like a jerk, but I get most of the auditions I go on. Because I go in beyond prepared. I make sure I know the songs better than the band themselves. I've learned also how to get along nicely with people

. I don't have a big mouth, I play well, I'm not an eyesore... I did however not too long ago go audition for a band I'd really have liked to have been a part of. Had no clue walking in that they were like 19-20 yrs old

. Incredibly talented though. We talked, I know they liked my playing, but it was pretty clear we weren't a match. I didn't call them, when they didn't call me.