EARS 2

Discover the exciting world of electroacoustic music and learn to make music with sounds.

Pitch

Pitch

Learn about how some sounds are high, and others low.

What Is Pitch?

The relative height of a sound, ranging from high to low.

A Few Pitches

Here are a few different pitches. Each of these are at a different height.

The three pitches in the soundfile above might be described respectively as:

  1. Low
  2. Medium
  3. High

Beyond Traditional Ideas of Pitch

In traditional musical notation, pitch is indicated along the vertical axis of the stave. The pitches of sounds can be quickly described as being low, medium or high. However, we can split this into as many registers as are required (e.g. Low-Medium, High-Medium, etc.).

Pitched Sounds

Sine Tone

This is a pitched sound. A sine tone is the most simple pitched sound.

You can see the simplicity and the focus of this sound energy by looking at a SpectrogramA way of visualising sounds that provides information about the frequencies that make up the sound.More infospectrogram of the sound.

Of course, not every sound has a clear pitch. Many noisy textures are spread across the pitch register and do not have a specific main focus.

Noisy Sounds

White Noise

A noisy sound which has no clear pitch.

Fact

Pitch can also be described in terms of FrequencyA technical term that describes pitch. The higher the frequency of a sound the higher it sounds in pitch.More infofrequency.

Frequency is a scientific term that describes pitch (just as H2O is a scientific term that describes water).

A high frequency sound has a high pitch, while a low frequency sound has a low pitch.


Multiple Pitches

Some sound sources produce more than one pitch.

Either at the same time:

North American Train Horn

This single horn sound contains multiple pitches playing at the same time.

Or one after the other:

Birdsong

This bridsong is a short melody of different notes following on from one another. Since the notes happen in quick succession, we hear this as a single gesture.

Fact

When we examine individual sounds in detail, we can discover that sounds are often made up of individual pitch elements. For more information, see: Complex Soundwaves.

TriangleWave
This is a SpectrogramA way of visualising sounds that provides information about the frequencies that make up the sound.More infospectrogram of a triangle wave. A single triangle wave is itself made up of many individual pitches, we see them here as stripes.


What Causes Pitch?

Pitched sounds are caused by regular vibrations. If an object vibrates in a regular way (moving back and forth smoothly), then it will create a pitched sound. The less regular the sound vibrates, then the noisier it is.

We can experience this by rubbing our finger around the damp rim of a glass to make it sing.

Activity

Singing Glass

flickglass

Instructions:

  • Ask someone at home if you can borrow a wine glass (or any glass with a stem).
  • Pick a glass that makes a good ring when you tap it.
  • Wet your finger and the rim of the glass.
  • Then, while holding the glass firmly with your non-writing hand, take the first finger of your writing hand and rub it smoothly and steadily around the rim of the glass.

Predicted Results:

  • If you are able to make smooth and steady regular motions around the rim, the glass should begin to sing, creating a pitched note.
  • If you move your writing hand in an irregular way around the glass, then no pitch will be created.

Why Is a Pitch Created?

The smooth and steady motion of the hand around the rim of the glass causes the glass to vibrate in a regular way, and thus produces a pitched sound.

Extra

By changing the level of liquid in the glass, it is possible to change the pitch. This is because the liquid dampens the vibrations where it touches the glass, thus changing the amount of the glass which is free to vibrate.

The more liquid in the glass, the smaller the surface that can vibrate and the higher the pitch produced.

This process is similar to the way in which changing the length of a string on a guitar or violin will change the pitch made (shorter string = higher pitch).


Changing the Pitch

Using technology, it is possible for us to change the pitch of sounds.

The process is known as Pitch Shifting This refers to the changing of the pitch in either direction. Traditionally pitch shifting went hand in hand with the change of speed of a tape recorder. More infopitch-shifting or TranspositionA manipulation which changes the pitch of a sound. More infotransposition. This technique is often used in pop music or cartoons to create high pitched voices.

For example:

Normal Voice

This is the original unedited recording.

Pitch-shifted Voice

This is the pitch-shifted version in which the sound has been increased in pitch.

This can be a really useful effect to transform and develop sounds. See: Transformations, for an example of the use of pitch-shifting in creating transformations.

Composition Tip

Try to use a mixture of high, medium and low pitched sounds in your compositions.

Using a range of different pitches allows you to fill up the whole sound range and provide a much richer soundscape.

Extra

Changing Pitch Over Time

Using AutomationA tool that allows you to change the variable parameters of a sound over time.More infoautomation it is possible to transform the pitch-shift of a sound over time. This can allow you to create GlissandoA pitch that changes over time.More infoglissandi and dynamic/changing transformations.

Pitch-shifted Clock

The amount of pitch-shift increases over time.

Find out more about how the Pitch Shifting This refers to the changing of the pitch in either direction. Traditionally pitch shifting went hand in hand with the change of speed of a tape recorder. More infopitch-shifting functionality works within Compose with Sounds.

Listening Challenge

Listen out for pitched sounds around you.

  • How would you describe their pitch?
    • Are they high/low?
    • Are they changing/constant?
    • Are there multiple pitches?