TASO football official here...
NCAA '11-'12 Football Rules:
Rule 1, Article 6.
a) All persons subject to the rules are governed by decisions of the officials.
b) Those persons subject to the rules are: Everyone in the team area, players,
substitutes, replaced players, coaches, athletics trainers, cheerleaders, band
members, mascots, public-address announcers, audio and video system operators, and other persons affiliated with the teams or institutions.
Rule 9, Section 2 (Unsportsmanlike Conduct Fouls), Article 1:
b) 5: Persons subject to the rules, including bands, shall not create any noise that prohibits a team from hearing its signals (Rule 1-1-6).
Penalty: Dead-ball foul. 15 yards from the succeeding spot (S7 and S27). Automatic first down for fouls by Team B if not in conflict with
other rules. Flagrant offenders, if players or substitutes, shall be disqualified (S47).
I've only seen this become an issue once in HS play. In a playoff game I was working last season, the band for one side was in the endzone bleachers. The opposing team had driven down to the red zone and before every snap, the band would synchronize a loud uncoordinated "blare" during the signal calling. No penalty was called, but the white hat walked over to the stands and told the band director or game administrator to stop the activity. They did...problem solved.