The spatial position of sound is one of the most important elements in our experience of sound.
Moving Sound Sources vs. Stationary Loudspeakers
Sound sources often move in the real world (e.g. a passing train, a swooping bird).
By using multiple loudspeakers we can reintroduce the impression of positioning and movement for sounds.
The most common setup is to have two loudspeakers, and this arrangement is known as stereo.
This type of setup is so common that most people simply refer to their music system as a ‘stereo’.
Stereo Sound Placement
There is no sound.
The sound appears to come from the centre.
The sound appears to come from the left.
The sound appears to come from the right.
Look below to see these same examples displayed graphically in an alternative view:
You can clearly see the differences between the four above sound examples within this Spectrogram view.
Sounds that are positioned on top of each other will compete and cover each other. Therefore, to be able to hear all sounds clearly we should use the panning tool in order to shift sounds to the right or to the left.
If we slowly change the proportion of left and right channel sounds – increasing the sound level in one loudspeaker while decreasing it in another – we can create the impression of movement.
Automation has been used to shift the balance of sound between left and right speakers. This makes the clock appear to move.
Beyond Stereo – Multichannel Sound
By using even more loudspeakers and positioning them behind, as well as in front of us (think about the surround sound in the cinema), we can create the impression of sounds moving all around us.
With multiple loudspeakers we can play with a space, just like we can play with sounds.
Panning allows us to move sounds about, and to begin to use space and spatial location as a tool in the composition process.
The idea of using space within a musical context is by no means new. The composer, Giovanni Gabrieli is known to have separated choirs at different sides of a cathedral in the late sixteenth century.
One of the most exciting things about sounds is that they come to us from all directions.
Max Neuhaus said, to ‘listen’ means, amongst other things, to recognise where sounds come from:
- Left and right.
- Front and back.
- Above and below.
- Far away or very close.
- In the foreground, middle ground, background, etc.
To hear how these sounds come to us from different locations can be a magnificent experience.
Imagine the following soundscapes:
Trees and nature surrounds us, creaks from trees can arrive from anywhere, an animal may make a cry from afar whilst another swoops very close to where you are sitting.
Insect sounds may surround you and sometimes you simply can’t quite tell exactly where they are coming from.
What else can you hear?
The city is all around us, so are its sounds. In fact, we often rely on our listening out for the location of sounds to keep us safe.
Think about the sounds of distant sirens from emergence vehicles, the sounds of cars and their horns whizzing past, the sounds of footsteps passing in the street and the sounds of aeroplanes overhead. The location that sounds come from doesn’t have to be static.
Think of traffic zooming past us. In fact, as a sound source changes its position/location we can often hear clearly how the sound changes.
Loudspeaker concerts use many loudspeakers to move sounds through a space. The loudspeakers are positioned all around the room, surrounding the audience.
Sounds come from all directions (e.g. behind, above, below, etc).