WHICH PITCH: 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 perceivedproperty of a sound, especially a musical tone, that

isdetermined by the frequency of the waves

producingit: 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 thefundamental frequency and the pitch.

The thickness, tightness, and material ofthe 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 thefrequency 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, sothe larger the wavelength, the smaller the

frequency.

Wavelength and Frequency

Longer pipes have longer wavelengths.

Longer wavelengths havelower frequencies.

Lower frequencies create lower pitches.

That’s why the longer raftpipes have a lower pitch!

Sikuras (raft flutes) from Chile

What do you know?

The of the pipe affects the pitch in windinstruments such as the panpipe. Frequency (f) is the number of made eachsecond 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 byour brains as pitches.

Want to Know More?

In other lessons, you can investigate the relationshipbetween frequency and pipe length as you make yourown panpipes.

Sikus (raft flutes) from Peru