That's the first time I've ever seen an official make a big deal out of the band. From the rulebook, "Persons subject to the rules, including bands, shall not create any noise that prohibits a team from hearing its signals (Rule 1-1-6)."
9-2-1-b-5 states that the clock stops when "The referee declares a timeout for unfair noise"
But I don't see anything else in there that specifically states that the band needs to stop playing when the offense reaches the line of scrimmage.