Learn how spaces influence, and add to, the sounds that travel through them and how this can be used in composition.
What Kind of Space?
No, not outer space! There are no sounds in outer space.
Sounds are affected by the spaces that they are in.
The echo under a tunnel or bridge is a perfect example of this.
- If we stand in the open and say something, then we only hear our voice travelling away from us.
- If we stand underneath a bridge, we not only hear our voice travelling away from us, but also bouncing back!
Close and Distant Sounds
If we listen (and if we are really quiet) then we may be able to hear what is happening outside of the current room. Perhaps there are footsteps, doors closing, people chatting, cars passing in the street, birds tweeting in the trees?
- Close your eyes and take a listen. Try to identify sounds that are close and those that are distant.
- Discuss these with a partner, did they hear the same sounds as you? Can you hear any new sounds now that your partner has mentioned them?
- How do you think these sounds might change if you left the room and stood in the corridor or outside?
How Space and Location Can Alter Sounds
The spaces which sounds are in can alter them.
Think of a string quartet or a gospel choir playing in the quiet setting of a modest concert hall. Then imagine the same performances within the more reverberant setting of a small church, or a hugely spacious train station, or even an enormous car park in the open air.
We will still be able to identify what we hear as the same sounds, but it will sound hugely different in each location.
Is it large/small, smooth/rough, busy/quiet, open/closed?
Reflected Sounds – Reverberation
Just like ripples in a tank, soundwaves can bounce back off of objects.
Soft objects will reflect less sound than hard objects.
Think, for example, of the difference between clapping your hands within the bedroom (full of soft furniture), and the bathroom (tiles and other hard surfaces).
How Does Reverberation Work?
In a reverberant space we hear a mixture of the original sound (coming directly to us – known as ‘Direct Sound’) and the reflected (known as ‘Reverberant Sound’) coming to us after having bounced of the surfaces of the space.
The first reflections to reach us are called ‘Early Reflections’. These tell us most about the qualities of the space we are in.
These sounds are not heard separately, but are blended and combined so that the reverberation mixes with the original sound to affect its quality.
Reverberation gives us a sense for the size of space that we are in, even without seeing it.
More Reverb – A / B / C / D
The same sound is repeated, but each time more and more reverb is added to the sound. Can you hear how the impression of size increases?
The sounds that we hear everyday are always influenced by some type of reverberation.
We hear a mixture of direct and reverberant sounds.
Early reflections are part of the reverberant sounds. These tell us about the qualities of the space we are in.
How Big Are These Spaces?
Listen to this sound and try to imagine the space in which it was recorded.
What size might this space be? Is this space larger or smaller than Space A?
Different Spaces – Hand Clap Test
In spaces with different properties, sounds will reflect and bounce around in different ways.
One good way of experiencing differences in reverberation is to listen to your own hand claps within different spaces:
- Stand quietly within a space and clap your hands once.
- Listen to how the sound decays.
- Move to another space and repeat.
- By comparing different locations, you will begin to hear how the sounds reverberate and bounce about within the space.
Try this in the living room, the corridor and the bathroom.
What in these rooms might be impacting upon the reverberation and the quality of the sounds?
Think about the difference between sounds within an empty room and a full room (perhaps try clapping your hands in an empty hall, and then again when the hall is full of people quietly waiting for assembly)?
Changes of Reverberation within a Single Room
Even moving about within a room can change reverberation.
Ask a friend to talk (or play an instrument) while walking around the room.
- How does the sound change as they move into different parts of the room?
- What does it sound like if they stand in the corner?
- Can you hear a difference if they stand outside the room in the corridor?
- Is it the same when they are close as it is when they are distant?
Reverb as Manipulation
Using computers we can synthesise the natural effects of reverberation.
The variables are:
- Room Size: This changes the apparent room size, affecting the scale of the space that the sound is in.
- Reverb Amount: This controls the balance between the direct and reverberant sound.
- Damping: This changes how reflective the virtual space is. From soft materials (wood/fabric) to hard (tiles/concrete).
When the material that the wall is made from is soft (for example, soft wood), then the reflections are lessened (high dampening). When the walls are made from hard materials (like tiles), then the reflections are high and the (low dampening).
A lively and reflective room with low dampening (hard surfaces).
Reverberation is dampened by the addition of soft furnishings.
Changing Reverberation Parameters
Moving from a close (dry) texture into a distant and diffused (wet) texture can be very effective (as can moving the other way from wet to dry).
Listen to this example which moves from dry to wet, and then back to dry again.
The above effect was created by increasing the amount of reverb added to the sound. How did this change your impression of the space? What did you imagine was happening?
Sometimes works are designed and composed with a specific space in mind. They will take advantage of the acoustic properties of that space (reverb) and use them musically.
These are called ‘Site-specific Works’. They might take place in a car park, church, under a bridge or anywhere that has specific acoustic properties that can be used musically.