Topics covered on this page: Time and sound – Sound waves – Pitch – Intensity – Timbre – Harmonics – Harmonic series
What is music?
Music can be defined as the artful organization of rhythm and sound. Any sound originates from a vibrating object and any object that can vibrate will make sound. These include common parts of familiar musical instruments such as a guitar string or a column of air in a flute, or even everyday objects like a squeaky balloon or a car horn.
There are terms used to describe the characteristics of sound and what we hear. Some basic terms are:
pitch – the relative “highness” or “lowness” of a sound
intensity – the relative loudness of a sound
duration – the relative length of a sound.
A clef defines the pitch range of the staff. A G clef or treble clef is seen below:
Many times in discussing music the word “relative” is used (relative pitch, relative minor, etc). This is because because of the connection or commonality between pitches, keys, or duration of other sounds in music. For example, a long piece of music or a high pitch is only considered long in relation to the length of other pieces or pitches.
The source of all sound is from vibrating objects.
Vibrating objects create energy in the form of sound waves which stimulate the ear and cause the ear drum to vibrate. The ear drum vibrates faster or slower depending on the vibrating object causing the sound waves. These sound waves are alternating compression and rarefaction of air molecules (or water molecules if a sound is underwater). The energy from vibrating objects create sound waves, and those waves travel through air, water, or other molecules around the object.
A closer look at a sound wave reveals the following:
The waves are called compression waves or longitudinal waves. One complete oscillation both above and below the central axis is known as a cycle.
When a sound is heard, the relative “highness” or “lowness” of a sound is referred to as pitch.
Faster vibrations from an object create higher pitch. Similarly, slower vibrations from an object create lower pitch.
An object’s vibrating speed is dependent upon several physical factors including its material, size, shape, and density.
Frequency determines pitch and is the number of recurring cycles per second. The unit of frequency is called Hertz (abbreviated HZ) and is named after scientist Heinrich Hertz. So when musicians commonly use the standard A=440HZ tuning, it means that the note A above middle C should have 440 cycles per second. An A with 880HZ will be an octave higher than the A at 440HZ. The pitch of a note with 800HZ will be lower than the pitch of a note with 900HZ.
The intensity of a sound is dependent on how hard the vibrating object is struck. A drum that is struck harder will create a louder sound with bigger vibrations than one struck softly which will create quiet sound and smaller vibrations.
When viewing a sound wave, the intensity of the sound is measured by amplitude. A sound created with more power will create a sound wave with greater amplitude. A sound created with less power will create a sound wave with lesser amplitude.
One analogy is it is like throwing a stone into a pond: A large stone creates more force and larger waves. A small stone create less force and smaller waves.
A sound’s characteristics which distinguishes it from others is called timbre. For example, both an opera singer and piano could play the same notes but timbre is what separates them from each other. Another example is distinguishing a sax from a trombone in a jazz combo. A sax has a different timbre than a trombone even if the two play the same note.
Duration is the length of time that a sound exists. When duration is used in music we commonly use rhythm to describe how long or how short a sound is.
Next section is The Notation of Pitch