High school bands apply law of physics to stay in step

Students competing in the 57th annual Cary Band Day will turn the football field into an applied physics lab. They have to if they want to win.

Posted 7:55 p.m. Oct 30, 2015 — Updated 6:55 p.m. Jul 13, 2018

Tony Rice

The cognitive benefits of music education in subjects like math and science are well documented. Students competing in the 57th annual Cary Band Day will turn the football field into an applied physics lab. They have to if they want to win.

Warning: math ahead

Sound travels at about 761 mph; light travels 873,500 times faster. If you’ve had the opportunity to see the space shuttle or other spacecraft launch, you’ve experienced that delay yourself. Spectators are generally at least 7 miles from the launch pad. The sight of the launch reaches you in a fraction of a millisecond but sound arrives about 30 seconds later. Marching bands must deal with this same law of physics to score well.

Each student on the field can play their part perfectly against their own internal metronome, but this is a recipe for “ensemble tear," or as judges often refer to it “phasing.” Bands must harness the speed of light AND sound to prevent phasing in competitions like Cary Band Day where first and second place can be separated by a few points.

A note played at the same instant from the far sideline arrives at the audience 130 milliseconds later than a note played on the near sideline. That may not seem like much but in the fast tempo shows performed by these bands, but the delay is very noticeable if not compensated for. Apex High School’s interpretation of jazz pianist Chick Corea’s “My Spanish Heart” reaches a tempo of 160 beat per minute, Without compensation for the speed of sound, the band could be off by 1/4 to 1/3 beat. Bands use various techniques to overcome the problem.

Moving formations are often designed to keep the drum line in the rear/center of the field. This allows the easily heard staccato drum sound to drive the rest of the band who “listen back” for tempo. Listening back is like a game of catch. Players in the back throw their sound forward, those mid-field catch it adding their own and so on. When performed correctly, everyone’s sound arrives at the audience at the same instant, solving the speed-of-sound problem.

When the drums aren't back there to drive the tempo, each performer must adjust based on their constantly changing location. Drum majors on the far sideline can help the band adjust by conducting 1/4 beat or more ahead of the drum major on the near sideline.

High school bands vary their playing and choreography to assure that a unified sound arrives at the stands. (Google maps/Rice)

“The less audible a steady pulse from behind is, the more you have to rely on what you see,” explains Daniel Jarvis, director of bands at Apex High School. “The further you go out from center, especially left-to-right, the more you have to play ahead.”

These bands are not just drums and horns. Many include a visual ensemble adding kinetic energy to the show with flags and rifles tossed high. These performers are spread out creating a palette of colorful flags and motion. However sound can take up to 1/2 beat to reach the outermost performers making synchronizing their movements with sound as it arrives at the audience even more challenging.

Through lots of rehearsals in the heat of summer and then before and after school, these little timing adjustments become part of each performer's muscle memory. They might not be doing the math in their heads as they perform, but they are doing something even better, becoming very familiar with a law of physics by experiencing it firsthand.

38 high school marching bands from central North Carolina and beyond are scheduled to compete at Cary Band Day at Cary High School Saturday, Oct. 31, from 9:45 a.m. until 11:00 p.m.

Temperatures will rise from the low 50s to the mid 60s by the afternoon. Clouds will increase throughout the day, but there is no rain in the forecast. Temperatures will drop back into the mid 50s by the time the Apex High School Marching Band performs at 9:45 p.m. The best seats are on the press box side of the field where all that sound should arrive together.

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