How Musical Instruments Work

This Expedition will explore the science behind common instruments found in an orchestra.

This story was created for the Google Expeditions project by Vida Systems, now available on Google Arts & Culture.

Every culture throughout history has developed their own form of music. Listening and creating music is clearly an important human experience. Musical instruments have evolved over many years to produce the clearest and most pleasing sounds.

What is sound?

Sounds are actually vibrations that pass through the air, ground, or water. The auditory systems of humans and animals have evolved to be able to hear these vibrations. Upon hearing the vibrations, the brain interprets what they mean.

Energy

Sound is a type of energy that is produced and when this energy is released, it pushes the air into little ripples called vibrations. The ripples continue until they run out of energy. If your ear is close enough, you will hear the vibrations.

Physical

Because sound is a physical product, we can feel the vibrations of some types of sound. If you ever stand near the speakers at a really loud concert, you can feel the low, bass notes vibrating in your body. 

Psychological

When sound vibrations reach the middle ear, they become a psychological product. As the inner ear transfers the vibrations into electrical signals, the brain interprets them.

Your brain's interpretation process helps you understand the sound's meaning: spoken words, a song, or a doorbell.

Medium

Sounds needs to travel through a medium, whether it be gas, liquid, or solid, because it needs vibrations to spread itself. You won’t hear sound in space, though, because it’s a vacuum, with no matter to act as a medium.

Woodwind

The woodwind section of an orchestra includes instruments such as the flute, oboe, clarinet, and bassoon. Their name comes from the fact that most of them were once made of wood, although today many are made of materials like metal and plastic.

All woodwinds produce sound by exhaling air over a sharp edge.

Reed

The bassoon produces sound using a reed. The bassoonist often makes the reed out of cane and wraps it in thread. The musician then pushes air through the sharp edge of the reed to create sound vibrations.  

Bocal

The bocal is a curved metal pipe that extends from the reed into the bassoon. A longer bocal means there’s a large volume of air pushed within (compared to a short bocal), which vibrates slower, producing the lower pitch. 

Joints

Bassoons consist of a number of joints. The length of the combined joints makes over 8 feet of pipe. To ensure the instrument is manageable, the joints fold back along themselves, creating an instrument that is 4 feet long instead. 

Bell

Air pushed into the reed travels 8 feet before a note is produced. Sound vibrates within the long tube before being released out of the bell. Keys are pushed to block holes, which stops air from escaping and changes the pitch of the sound.

Brass

Brass instruments are the loudest instruments in an orchestra. Made out of the metal brass, these instruments also require air to be pushed through in order to produce a sound. Unlike woodwind instruments, however, brass instruments don’t have a reed. 

Mouthpiece

Air is forcefully pushed into the trumpet via the mouthpiece. As brass instruments don’t have reeds, the musician produces sound by buzzing the lips while blowing. Changing the shape of the lips and using the trumpet’s valves changes the pitch. 

Valve pistons

Valve pistons pressed by the musician change the trumpet’s notes. Each valve has different pathways, like little tunnels bored through them. Pressing a valve forces the air into a U–shaped tunnel and extra piping, lengthening the amount of pipe the air needs to travel.

Piping

Altogether a trumpet consists of over 6 feet of piping. Curving the pipe allows the musician to hold and manipulate the instrument easily. The further vibrating air travels through the piping, the lower the pitch produced. 

Bell

The bell amplifies the sound as the energy of the vibration is released from the trumpet. Changing the material the bell is made out of, for example, coating it in sterling silver, changes the sound produced.

String

A string instrument, as the name suggests, produces its sound using a series of strings that stretch across the instrument. Many types of instruments exist within this family, such as the harp, guitar, and violin. 

They make up the majority of the instruments found in an orchestra.

Violin

Many stringed instruments only require the musician to pluck, pick, or strum the strings and make them vibrate. A violin however, requires complex interaction between a bow, the strings, and the body of the violin itself. 

String

Shortening the length of the string by placing fingers on it changes the notes played. How tight the string is stretched across the body affects the pitch of the note and even the material the string is made out of influences the sound produced. 

Bow

The bow, with lengths of coated horse hair looped across it, is dragged across the strings on the violin. The force applied, the angle in which the bow is tilted, and which strings are struck all change the sound produced.

Body

The strings make the body vibrate, with sound waves being amplified by the body’s cavity. How the body is crafted can vary the sound produced widely. Most violins have shapes like an hourglass, although some have been made with a trapezoid shape.

Piano

The piano was invented in the 1600s in Italy. Its name comes from pianoforte, meaning loud and soft, because the musician could control the volume of sounds produced.

Pianos are technically a percussion instrument, an instrument that requires a hammer to strike in order to produce its rich sound. 

Keys

Pianists press down on one or a combination of keys. Most modern pianos have 88 keys: 36 white keys that play the notes A through G at various octaves, and 52 black notes that play the flat and sharp version of the notes.

Damper

The harder the pianist strikes the key, the harder the hammer hits the string and the louder the sound that is produced. The damper stops the string from vibrating, controlling how long the sound waves occur.

Hammers and strings

Attached to each key is a small, wooden hammer. The hammer strikes one of 230 steel strings, vibrating the string and producing sound waves. The length of the string, the diameter of the string, and the tension of the string all change the note produced.

Percussion

A percussion instrument requires the musician to strike the instrument with another implement. Popular percussion instruments include the triangle, tambourine, xylophone, and all types of drums. Other than singing, percussion instruments are the oldest form of music production.

Drums

A drum is typically a hollow cylinder that is played by striking it with an implement. When the drum is struck, the air inside becomes compressed. As the compressed air bounces back it creates a vibration, producing sound.

Snare

A snare drum contains a wire that is strung under the lower skin. This ensures the snare drum produces a stucco type sound. Very versatile, snare drums can be used create a huge variety of sounds.

Bass drum

The bass drum is the largest drum in a drum kit. It produces a deeper sound compared to the other drums. Drummers play it by pressing a foot pedal that pushes a felt–covered hammer into the bass drum. 

Tom toms

Although it looks similar to the snare drum, the tom tom doesn’t have wires stretched across its skin. While the tom tom shell is traditionally made of wood, modern drums often use materials such as fiberglass or pressed steel.

Hi-hat

Hi-hats are composed of 2 brass cymbals mounted on a metal stand that are pushed together when the musician presses a foot pedal. Musicians also strike the hi-hats with a drumstick to create a different sound.

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