Studio work: Generally, if you're going to work for a studio, you need to look nice, but will suffer in business attire. Working at studios involves some lifting, and it's fast pace makes wearing a full suit a hassle. Additionally, it's very likely that whoever is interviewing you will be in casual or business casual attire. Try business casual: a button down shirt, slacks, shoes and belt. If you want to trade for a nice looking sweater, that's fine, but keep the tie out of the equation.
Venue: the best thing to do when looking into applying for a venue is to physically go there. Not only does this give you the feel for the environment, you can also pick up dress code ideas from the people already working there. Take a look at the FOH engineer, is he wearing a t-shirt or a button down. Now note, no matter what the employees are wearing, DO NOT go to your interview in your favorite Slayer tour tee. Interviews, no matter what type, require some kind of tact, so if you see an extremely dressed down environment, opt for a polo or a nice, solid-colored tee instead.
In short, the name of the game is "classy, but not over-classy" favor nice, dress clothes over full on suits, shoes over sneakers, and slacks over jeans. Don't pour on the business attire like you're applying to be CEO of a Fortune 500, but at the same time, you're not appying for a McDonald's job, so coming in dress-down clothes doesn't work either.