Layers of Sound
Sounds occur in layers, some will be in the foreground and others in the background.
When working with many different layers of sounds, we need to be able to control and balance them so they fit harmoniously together.
Sounds can move between layers, and whole layers can even switch around.
We can divide the soundscape into two main layers: local and field.
Local and Field
The field operates as a background layer against which more local objects can be defined, while local objects are more focused, and are foregrounded against the larger field.
An interesting fact is that the local cannot exist without the field. If the field is removed, then the local loses its definition. The sound may still exist, but it has nothing to relate to.
Each is defined by the other.
Sometimes local sounds may need a specific background field against which to reach their fullest potential.
Try experimenting with different background textures until you find one that makes your local sound stand out most.
Sometimes, these two layers are not enough and we need to talk about many more layers. We can further divide up the local by introducing three subcategories: arena, stage and event.
Arena, Stage and Event
Imagine an open air music festival taking place on a farm. The largest layer is the whole field in which everything takes place. But within the field, there are a few distinct arenas (playing different kinds of performances). Inside each of these arenas, there are individual stages containing different performances, and on each stage, there are different individual events (an individual piece of music).
Now imagine that you’re at this festival, listening to your favourite musician playing your favourite piece of music.
- The favourite piece of music is the EVENT.
- The favourite musician is performing on a specific STAGE.
- Beyond this stage are the other ARENAs of the festival.
- And at the largest extremity is the whole FIELD.
When you stand listening to your favourite musician, you may hear sounds from the rest of the arena float over, but your main focus will be on the local, the musician (the STAGE) and the particular piece of music that they are playing (the EVENT).
However, as you move around the festival, your relationship to each layer of sound will change.
If you decide to leave the music stage and move into the comedy arena, the balance of sounds will shift and the comedian’s joke will become the EVENT, while the original musician becomes part of the field, performed upon a distant stage within a different arena.
Sounds and Distance
The character of a sound changes as it shifts further away from the listener.
Think back to our festival example and imagine that there is an Electronic Music group playing on one of the stages. When we are far away, outside of the festival field, we will hardly hear their sounds.
When we enter the FIELD and move towards the ARENA, in which they are playing, we will hear their sounds at a low volume. We will also hear much more of the bass component of their sound. This is really significant and is caused by the fact that low frequency sounds are able to travel long distances before fading out.
As we move closer and closer to the STAGE and EVENT, we will hear progressively more and more of the mid and higher frequency components of the sound. This is because these high sounds can only travel short distances before fading out.
Creating Realistic Layers
Knowing why and how the sounds that we hear differ, depending upon our relative distance from them, we use this information to reverse engineer the process.
We can transform sounds recorded with very close microphones, and make them sound as if they are very far away.
The closer we are to sounds, the louder they will appear.
Louder sounds appear closer, while quieter sounds appear further away.
Using automation we can begin to get these sounds to shift. The loudness of one layer may increase, making it appear to move closer to the listener. While the loudness of another layer may decrease, giving the impression that this layer is moving away from the listener.
This sound begins quietly and is positioned slightly off to the left. This gives the impression that the sound is far away and in a specific location. As the volume increases, the impression is that the sound gets closer.
Filtering – Low-Pass
As we learnt above, high frequency sounds can only travel short distances before fading away. So, as sounds move away from us, the high frequency component that we hear also drops off, leaving only the bass.
We can simulate this with a Low-Pass Filter. By setting the cut-off, we can control how much of the high frequency sounds we allow through. Setting the cut-off for the Low-Pass Filter at a low point will create a more bassy sound, the kind that we would expect to hear from a distant object.
Combined Processes for the Full Effect
In practice, both loudness and filtering are operating alongside one another. Therefore, in order to create a realistic effect, we need to edit and automate both in tandem.
We can hear this in action when we listen to natural sounds that are approaching us:
This sound naturally gets closer to us. Listen to how the frequency range of the sounds change over time and the volume increases. At first, we only hear the quiet and low rumble of the train. But gradually, we begin to hear more and more of the higher frequency sounds as the train approaches and gets louder and louder.
As we learned above, low sounds are often more powerful than high sounds (this is the reason that they can travel further distances). But there is the danger that these powerful low sounds may overpower the more delicate high sounds.
When combining sounds in our pieces, we need to make sure that these low sounds are not masking higher frequency sounds. We can do this in a number of ways:
Pan to Spread Sounds Out
We can pan sounds apart so that they no longer overlap. Moving low sounds one way and high sounds the other way will help to separate them out into different speakers and help to eliminate masking.
Use a Filter or Equaliser
Filters and equalisers allow us to alter the balance of frequencies within a sound. We can boost some sounds while cutting others. For example, boosting high frequency sounds while cutting low frequency sounds.
Finding a Good Balance
There are no set rules to help you find the perfect balance.
You will need to use your ears and listen out for what sounds right.