Percussion and Science

CurioCity
23 January 2012

Put your hand up if you don't like music...

Right.

That's what I thought.

Most of us dig some kind of music and chances are that music has a beat and a rhythm; that is, it has some form of percussion.

Percussion is the sound of something beating, hitting or gently tapping another object to produce a sound or vibration or simply put, pushing air. And depending on how exactly that air is pushed towards our ears, it can make us want to slam dance or close our eyes and go "mmmm, oh yeah."

The percussionist is one of the most powerful controllers of our emotions. They are commonly referred to as "the backbone" or "the heartbeat" of a musical ensemble. Think of The Killers without Ronnie Vannucci Jr. or Simple Plan without Chuck Comeau — hard to imagine.

Did you know? Maple is one of the lightest wood types used for drumsticks Our musical experience is all thanks to a harmonious marriage between how we interpret events and science. Yes, music is all about physics and math, even though we aren't aware of it most of the time.

Show me the Physics!

Music is physics at its best — without vibration, sound waves, frequency, pitch, resonance and overtones there would be no Bach, no Gwen Steffani... there would also be no Jim Faraday — a professor of the Dalhousie Music Department in Halifax.

Faraday has travelled the world as a percussionist and has played every type of percussion. Naturally, he has a lot to say about how music can make us groove. He says that all music starts with vibration.

Vibration

All sound starts with vibration. When a drum is hit, the drum head vibrates and pushes against the air, creating small areas of compressed air. That compressed air pushes against the air around it, which in turn pushes against the air around that, and so on. And then it happens: rarefaction.

Did you know?  The oldest known drums are from 3000 BC Areas of less pressure, or rarefaction, are created between the compression pulses when air travels past the original areas of compressed air. You end up with areas of compression and areas of rarefaction that travel outward from the drum, one after another at a rate equal to the rate of the drum vibration. These are sound waves.

Frequency and pitch

Sound waves have a frequency which is the rate at which the waves pass a given point. The physical distance between compression pulses are wavelengths which is inversely proportional to the frequency. Sound waves also have amplitude, which is the amount of air that gets moved with each pulse of pressure.

When pulses of compressed air (sound waves) stimulate your eardrum and inner ear, it sends signals to your brain and you start to hear music. In general, you perceive the frequency of the wave (measured in hertz (Hz)) as a particular pitch.

Crank it up! Resonance and Overtones

If you like your music loud, resonance can help. Resonance occurs if a vibration or sound wave can excite another object into vibrating, creating more volume.

Overtones refer to any resonant frequency above the main frequency. Since the vibrating instrument (or air for that matter) does not just vibrate as a whole, sound waves of more than one frequency are produced. These additional frequencies are usually even multiples of the vibration frequency of the main object.

Did you know? The butt is the counter balance point of the drum stick For example, if part of a drum vibrates at 440 times per second, generating sound waves with a frequency of 440 Hz, it may also generate waves with a frequency of 880 Hz (2 x 440) and 1,320 Hz (3 x 440). When the overtones are close to even multiples of the main frequency, our brains interpret all the frequencies as a single pitch.

Ok, but where is the Math?

Math and music have strong links in history. In fact, the Pythagoreans, (remember the theorem regarding the square of the hypotenuse of a right triangle?) used harmony and rhythm as a basis for their mathematical ideas. Johann Sebastian Bach is famous for using a highly calculated approach to composition and sometimes used hidden numerical systems in his compositions.

Nowadays, some scientists believe that learning music improves mathematical abilities. Proponents of the controversial "Mozart-Effect" claim that listening to music at an early age increases spatial-temporal reasoning - essentially making you smarter.

Rhythmically, music is based on the subdivisions of time into fractions. These fractions (beats per measure) are represented in different time signatures.

The style of the beat also affects the music you hear and feel. A very common beat is the "backbeat" which means playing the second and fourth beats of the bar (even beats) to create a strong accent. This tension between the normally much stronger first and third beats (downbeats) and the backbeats creates an effect called syncopation.

Math Rock

"Math Rock" or the harder "math core" are styles of rock and heavy metal music that purposely use math to twist complex and atypical rhythmic structures together. They use stop/start dynamics or musically "clashing" riffs to create a sound that is somehow "off".

Math rockers like to mix it up by using constantly changing or odd time meters like 7/8, 11/8 or 13/8. Odd numbers are considered to have movement, and not be as stodgy as 4/4.

The Pulse of Life

It started before we were born; the common experience of hearing our mother's heartbeat. So whether you like The All American Rejects, Kanye West or Mozart, at the level of science, they are all the same. For Jim Faraday, science and music always go hand in hand. "My job is to stimulate technique, knowledge of science and imagination," he says, "after that my students can do anything."

Learn More!

Math and Music. Click Here

Fun Rhythm Exercises :

www.sju.edu

www.soundpiper.com

Can music make you smart? (Mozart-effect)

www.sedl.org

http://en.wikipedia.org

Interactive sound waves

www.grc.nasa.gov

Math Rock:

www.epitonic.com

Teaching Percussion by Gary D. Cook

Special Thanks: Jim Faraday, Dalhousie University, Halifax, Nova Scotia

Sonya Poller is a journalism student at the University of King’s College in Halifax, Nova Scotia. Her passions are documentary filmmaking and jazz music. She recently lived in Germany for over four years where she learned the joys of language, culture – and great food!

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