W HICH P ITCH: How Do We Know? Kudu horns (side-blown trumpets) from South Africa

Musical Instrument Museum (MIM) Electric guitar from USA Sikuras (raft flutes) from Chile Taiko (double-headed barrel drum) from USA Gong from Thailand Morin khuur (bowed spike lute) from Mongolia

Making Sound: What’s Vibrating? Aerophone (clarín, quena, sikus) – the air inside the instrument vibrates. Chordophone (charango, harp, violin, morin khuur) – the strings vibrate. Idiophone (triangle, ketuk, slit drum) – the instrument itself vibrates. Membranophones (djembe, goombay, bongos) – the membrane vibrates when struck.

Pitch: Intersecting Music and Science Musically speaking, pitch is defined as the location of a note, depending on its highness or lowness. Scientifically speaking, pitch is an aurally perceived property of a sound, especially a musical tone, that is determined by the frequency of the waves producing it: the highness or lowness of sound.

The Long and Short of It: Chordophones Can you predict the pitch of a stringed instrument (chordophone) by looking at it? How does string length play a part? Guitar and double-bass from Argentina Morin khuur from Mongolia

For Strings The longer the string, the lower the fundamental frequency and the pitch. The thickness, tightness, and material of the string also matter! Nyckelharpa (bowed lute) from Sweden Violin from Germany

Aerophones Is there a similar correlation among pipe instruments, for instance, aerophones such as a trumpet or a tuba?

What About Other Pipe Instruments? Organ Pipes Pipe organ from USA Portative pipe organ from Peru

What About Other Wind Instruments? Rondador (raft flutes) from Ecuador Musical jug from USA Over-the-shoulder horns (valved horns) from USA

Types of Pipes: Open and Closed Open ended pipes: both ends are open organ pipes Closed ended pipes: one end is closed musical jug, trumpet, raft flutes At the correct frequency, the air column resonates (we’ll get to resonance in a bit).

Open Ended Pipes At the open end, air molecules can move a lot –In the drawings, you see the curves far apart where the air moves a lot; those positions are called antinodes In between the antinodes, there are places where the molecules don’t move much; those positions are called nodes.

Closed Ended Pipes At the closed end, molecules don’t move much. –Nodes exists at the closed end, antinodes at the open end. The nodes are farther apart than in an open pipe, so the wavelength is longer and the pitch is lower than for an open pipe.

Wavelength and Pitch The closer the nodes are to each other, the shorter the wavelength of the wave, measured in meters. The top drawing shows the longest wavelength; the bottom one represents the shortest wavelength.

Frequency and Sound Frequency (f) is the number of vibrations made each second and is measured in Hertz (Hz). For sound waves, the pitch corresponds to the frequency of the sound wave. Higher frequencies of sound waves are interpreted by our brains as higher pitches.

Wavelength and Frequency Wavelength and frequency are inversely related, so the larger the wavelength, the smaller the frequency.

Wavelength and Frequency Longer pipes have longer wavelengths. Longer wavelengths have lower frequencies. Lower frequencies create lower pitches. That’s why the longer raft pipes have a lower pitch! Sikuras (raft flutes) from Chile

What do you know? The of the pipe affects the pitch in wind instruments such as the panpipe. Frequency (f) is the number of made each second and is measured in Hertz (Hz). For sound waves, the pitch corresponds to the of the sound wave. Higher frequencies of sound waves are interpreted by our brains as pitches.

Want to Know More? In other lessons, you can investigate the relationship between frequency and pipe length as you make your own panpipes. Sikus (raft flutes) from Peru