I was at Chelsea Studios today and they were in rehearsals there.
Typically you'll do a couple 10 out of 12s (meaning you work 10 hours out of 12 hours) for a tech and then start previews. So, I would imagine for a show that isn't too tech heavy, they could have one day of tech and then start previews the next day.
Updated On: 3/27/14 at 12:54 AM