OHSAA Handbook says this:
12. Bands
A. It shall be the responsibility of the host school’s Athletic Director to notify the visiting
school’s Athletic Director whether the visiting school’s band will be permitted at its
homecoming.
B. The half-time intermission shall be limited to 20-minutes. The clock will start immediately
when both teams and the game officials clear the field. At the conclusion of 20-minutes, a
three-minute warm-up period is required for both teams and will be timed on the game
clock.
C. If the bands of both competing schools are to perform at half-time, no more than 9-
minutes shall be allotted to the host schools band for its performance and no more than 9-
minutes shall be allotted for the visiting schools band performance.
D. A full band is not permitted to play through amplified microphones during the football
game.
E. Bands shall assemble and stay outside the field of play and end zone until the first half
has been completed before coming onto these areas. The same shall be repeated at the
end of the game.
F. The home team’s band shall not be seated behind the visiting team’s restraining area
which is commonly referred to as the 25 to 25 yard lines.
G. Bands shall not play music at football games while the ball is in play, or while signals are
being called by the quarterback. This means that it is not permissible to use either:
1. Drum roll or beat
2. Cymbals clashing
3. Horn sounds, or
4. Any other kind of musical instrument while the play is underway in football.
H. Roving bands shall be allowed to participate at the discretion of the host Athletic Director.
However, such bands shall not perform while the ball is in play or while signals are being
called by the quarterback.
Also, the roving band shall not perform behind the visiting team’s bench area. If a roving
band is found in violation of this agreement, that band shall be suspended from roving the
remainder of that season at any football games.
http://ohsaa.org/sports/ft/boys/manual.pdf