Natural White Noise

So much has been written about white noise and how it can be used, that for some people it has taken on a magical aura. Actually, it is just simply random noise, and it sounds like that SHHHH sound that you hear when you tune an AM radio set to an empty channel. (If you use a TV or FM radio set, make sure the noise squelch on the set is off, or it will seem magical – there won’t be any noise!) What makes white noise useful is its ability to mask other environmental noise and also mask the noise of tinnitus. The purpose of this article is to explain why noise recorded from nature is easier to listen to and better for you, than machine generated white noise.

Why is it called “White”?

In theory white noise is random energy across the range of our hearing. White noise, in theory, has similar audio properties when compared to white light and its visual properties. White light is just random energy across our range of vision. But – and this is a real big “but” - only in theory. In reality, white noise doesn’t sound the way one would think it should. This is because our sense of hearing divides our hearing spectrum into equal intervals called octaves. Each octave represents a doubling of frequency and what this means is that the highest octave of our hearing will contain half of all the frequencies we hear. A random noise such as “white noise” therefore sounds like a high “shhhhhh” because half of its energy is present in the very highest octave of our hearing. And that top octave is the only about 12% of our hearing range when measured in octaves. This is why masking environmental noise in the mid or low range of our hearing with white noise is difficult. Examples of natural white noise.

Pink Noise to the Rescue

Well, this information about white noise is not new, and there is a better solution which does sound about equal across our entire listening range. It is called pink noise. Pink noise has more energy in the lower end of the frequency spectrum so that we hear the same amount of bass and midrange sounds as we do high sounds. It is called “pink” because if you did the same thing with light, you would see pink light. Pink noise is a better solution to mask unwanted environmental noise, and low rumbles.Examples of natural pink noise.

Noise Sources

Noise is real easy to create with electronics. In fact, a major design problem in audio electronics - if not the most important consideration - is to try and minimize the presence of noise. I have tried using machine-generated noise in the past. (of course, not in my nature sounds!) However, nothing beats or compares to the quality and relaxing effect of sounds found in nature. That is why I spend a lot of time and money to go out and record natural noise. It is simply worth it! For constant sources of random noise, nothing beats running water. Waterfalls tend to be a perfect constant source for pink noise, and streams and rivers usually yield a better white noise. Shore waves can be used as a source of either type of noise, with a stronger rhythmic element.

Rhythmic Randomness

A sound recorded from nature has a depth, clarity, and an inherent playfulness that is not present in artificial noise. Whether we notice it or not as we listen to it doesn’t seem to matter because with nature sounds, the feeling of comfort is happening at the sensory level, and not with the intellect directly. Our senses evolved and were created to be comfortable with natural stimuli, and this means that we are naturally more comfortable listening to natural sounds than to artificial ones. The difference is the presence of rhythmic randomness in nature. For more information about rhythmic randomness, please see Friday October 16, 2009 in this blog.

Karl Hamilton BFA
Nature Sounds.ca
www.naturesounds.ca
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