Layers of Sound
When listening to field recordings, people soon recognised that animals communicated to each other using different pitch ranges.
Natural Frequency Selection
Explore the soundscape above, which has been split into separate frequency bands. Roll your mouse over each animal to hear their sounds.
This is a natural soundscape, within which each creature can be found calling in a different discrete band. Animals use these discrete bands so that they are not interrupted by other animals. Each animal calls out within its own niche.
The researchers who noticed that this banding occurs in nature gave it the name ‘Niche Hypothesis’.
A small gap.
A theory based upon some evidence that encourages further thinking.
Because sound wave vibrations can interfere and overpower one another where they overlap, animals evolved to separate their call sounds into different bands of frequency so as to avoid (or reduce) this overlapping.
Very high frequency - often creating very dense clouds of constant high frequency noise.
Quite high in frequency - intermittent with an assertive tone.
Medium frequency - many changes and a clear timbre.
Low frequency - strong and powerful sound.
The Same Is True in Music
This idea also works within music. Orchestras and pop bands have evolved to contain a range of instruments so that they can fill all the different frequency bands (low to high). Where sounds exist in the same frequency band, they often have a different timbre (so that they do not overlap).
Avoiding overlapping can be very useful for retaining clarity in our own compositions.
- Make sure that your sounds do not overlap too much.
- If you have sounds in the same frequency area, make sure that they have different sound qualities and perhaps pan them apart.
- Use transposition and filtering to move sounds into individual pitch ranges.
The soundscape of habitats function like an orchestra, with each creature’s voice occupying its own place within the soundscape according to its PitchThe relative height of a sound, ranging from low to high.pitch, LoudnessThe relative volume of a sound, ranging from loud to quiet.loudness, TimbreThe colour or quality of a sound. A combination of all other properties that makes each sound unique. timbre, and DurationLength in time. In our case for a sound, or a group of sounds.duration of sound.
As more and more creatures/instruments vie for a limited acoustical space, the ability to clearly stand out against the rest of the soundscape becomes even more important to each species’ survival.
Sometimes animals change their natural sound patterns to avoid this overlapping process depending upon their environment. One example of this is where birds change their singing patterns in city soundscapes. The city is very loud and noisy (with sounds at a wide range of frequencies) and it has been shown that where there are many low frequencies, some birds adapt to sing at a higher pitch.
Considering the Whole Soundscape
But while we can focus in on individual points and events within the soundscape, it is also really important to recognise how all of the elements fit together and only make complete sense when they are all heard as a whole.
We can compare this to only listening to the drum pattern of a pop song, ignoring all of the other instruments and voice. When we only focus on one aspect, we miss out on the many relationships between sounds and their context.
The phrase, “Can’t see the wood for the trees” also demonstrates this same effect.
If you are paying a lot of attention to individual details, you might miss out on the bigger picture.
Thinking about how the different parts of a soundscape fit together can be really useful for us when seeking to understand a soundscape, and can provide inspiration for our own creative practice, where we create musical works (in any genre).
Discover more wildlife sounds by visiting The Great Animal Orchestra website.
The sound recordings are by Bernie Krause, the man who coined the idea of the ‘Niche Hypothesis’, and the website is designed to work in partnership with a book of the same name.
The ideas of the Niche Hypothesis and the recordings that Bernie Krause has made also inspired the development of The Great Animal Orchestra Symphony.