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The Colors of Noise
We've all heard of "White Noise"...probably even saw the flick (I gave it a two
thumbs down...or as they used to say "Hated it...").
Remember; Sound and Light obey the same laws of reflection. And with that
being said - because the Spectrum of Sound Wave Frequencies are similar to the
Spectrum of Light Wave Frequencies the different colors apply to different types
of noise based on their distinct frequencies and characteristics. Thus, if the
sound wave pattern of Pink Noise were rendered into light waves, the result
would be Pink Light, etc.
We all know that "White Light" is a combination of all colors in the visible light
spectrum. When "White Light" shines through a prism (or water vapor, like when
you see a rainbow); the "White Light" is broken apart into the colors of the visible
light spectrum.
Definitions of the Colors of Noise
Black Noise; is noise that has a frequency spectrum of predominantly zero power
level over all frequencies except for a few narrow bands or spikes. Basically,
Black Noise is silence, no noise at all.
Blue Noise; aka Azure Noise, is similar to Pink Noise except the power density
increases 3 dB per octave as the frequency increases. In technical terms the
density is proportional to the frequency. This can be good noise for dithering
(digital audio processing technique used to prevent sound distortion).
Brown Noise; has more energy at lower frequencies (decreasing by around 6dB
per octave). To the human ear, Brown Noise is similar to White Noise but at a
lower frequency. Examples in nature include waves on the beach and some wind
noise.
Green Noise; said to be the background noise of the world. It is the mid-frequency
component of White Noise. Ambient noise averaged from several different
outdoors locations, similar in sound to Pink Noise with an emphasis on the range
around 500Hz.
Grey Noise; is a random noise which sounds the same at all frequencies to the
human ear. This is not the same as White Noise, which has the same energy at
all frequencies. Grey Noise is subjected to a psycho-acoustic equal loudness
curve which compensates for the bias of the human ear so that it sounds the
same at all frequencies. (Psycho-acoustic is the study of sounds or acoustics
perceived by the human ear).
Orange Noise; relates to musical scales, the bands of zero energy coincide with
the notes in the scale. This means that the "in-tune" notes of a scale are
removed, leaving only the "out-of-tune" frequencies. It creates a clashing,
displeasing noise, since all "in-tune" musical notes are eliminated, the remaining
spectrum consists of "sour" or "Orange Notes”.
Pink Noise; is similar to White Noise except that it contains an equal amount of
energy in each octave band. Sound Engineers use Pink Noise to test whether a
system has a flat frequency response. Pink Noise can be generated by putting
White Noise through a Pinking Filter which removes more energy as the
frequency increases (approximately 3 dB per octave). Each octave contains the
same amount of power. As White Noise is similar to White Light (representing all
frequencies equally); Pink Noise is similar to light which leans towards the lower
end of the visible light spectrum - Red Light. Cool Edit Pro's Definition: Pink Noise
has a spectral frequency of 1/f and is found mostly in nature. It is the most natural
sounding of the noises. By equalizing the sounds, you can generate rainfall,
waterfalls, wind, rushing river, and other natural sounds. Pink Noise is exactly
between Brown and White Noise (which is why some people used to call it Tan
Noise, but Pink was more appealing). It is neither random nor predictable. It has a
fractal-like nature when viewed. When zoomed in, the pattern looks identical to
when zoomed out, except at lower amplitude.
Purple Noise; is similar to Brown Noise except that the power density increases 6
dB per octave as the frequency increases.
Red Noise; is another name for Brown Noise, and an oceanographic term which
describes the ambient noise of distant underwater objects due to the selective
absorption of higher frequencies. The color "Red" refers to the loss of higher
frequencies with an emphasis on lower frequencies (this is from the White
Noise/White Light analogy and applies to either of the above definitions).
White Noise; a random noise that contains an equal amount of energy in all
frequency bands. White Noise is the equivalent of White Light and is how it gets
its name. White Light is made-up of all light frequencies (colors), while White
Noise is made-up of all audio frequencies. White Noise is used in electronic
music, either directly as a sound effect or as the basis to create other noises. For
example, many percussion instruments have a high component of White Noise.
White Noise is also used to mask other sounds. This process takes advantage of
the way the human brain works; the brain is able to single-out simple frequency
ranges but has trouble when too many frequencies are heard at once. When
White Noise is present, other noises appear diminished.
We've all heard of "White Noise"...probably even saw the flick (I gave it a two
thumbs down...or as they used to say "Hated it...").
Remember; Sound and Light obey the same laws of reflection. And with that
being said - because the Spectrum of Sound Wave Frequencies are similar to the
Spectrum of Light Wave Frequencies the different colors apply to different types
of noise based on their distinct frequencies and characteristics. Thus, if the
sound wave pattern of Pink Noise were rendered into light waves, the result
would be Pink Light, etc.
We all know that "White Light" is a combination of all colors in the visible light
spectrum. When "White Light" shines through a prism (or water vapor, like when
you see a rainbow); the "White Light" is broken apart into the colors of the visible
light spectrum.
Definitions of the Colors of Noise
Black Noise; is noise that has a frequency spectrum of predominantly zero power
level over all frequencies except for a few narrow bands or spikes. Basically,
Black Noise is silence, no noise at all.
Blue Noise; aka Azure Noise, is similar to Pink Noise except the power density
increases 3 dB per octave as the frequency increases. In technical terms the
density is proportional to the frequency. This can be good noise for dithering
(digital audio processing technique used to prevent sound distortion).
Brown Noise; has more energy at lower frequencies (decreasing by around 6dB
per octave). To the human ear, Brown Noise is similar to White Noise but at a
lower frequency. Examples in nature include waves on the beach and some wind
noise.
Green Noise; said to be the background noise of the world. It is the mid-frequency
component of White Noise. Ambient noise averaged from several different
outdoors locations, similar in sound to Pink Noise with an emphasis on the range
around 500Hz.
Grey Noise; is a random noise which sounds the same at all frequencies to the
human ear. This is not the same as White Noise, which has the same energy at
all frequencies. Grey Noise is subjected to a psycho-acoustic equal loudness
curve which compensates for the bias of the human ear so that it sounds the
same at all frequencies. (Psycho-acoustic is the study of sounds or acoustics
perceived by the human ear).
Orange Noise; relates to musical scales, the bands of zero energy coincide with
the notes in the scale. This means that the "in-tune" notes of a scale are
removed, leaving only the "out-of-tune" frequencies. It creates a clashing,
displeasing noise, since all "in-tune" musical notes are eliminated, the remaining
spectrum consists of "sour" or "Orange Notes”.
Pink Noise; is similar to White Noise except that it contains an equal amount of
energy in each octave band. Sound Engineers use Pink Noise to test whether a
system has a flat frequency response. Pink Noise can be generated by putting
White Noise through a Pinking Filter which removes more energy as the
frequency increases (approximately 3 dB per octave). Each octave contains the
same amount of power. As White Noise is similar to White Light (representing all
frequencies equally); Pink Noise is similar to light which leans towards the lower
end of the visible light spectrum - Red Light. Cool Edit Pro's Definition: Pink Noise
has a spectral frequency of 1/f and is found mostly in nature. It is the most natural
sounding of the noises. By equalizing the sounds, you can generate rainfall,
waterfalls, wind, rushing river, and other natural sounds. Pink Noise is exactly
between Brown and White Noise (which is why some people used to call it Tan
Noise, but Pink was more appealing). It is neither random nor predictable. It has a
fractal-like nature when viewed. When zoomed in, the pattern looks identical to
when zoomed out, except at lower amplitude.
Purple Noise; is similar to Brown Noise except that the power density increases 6
dB per octave as the frequency increases.
Red Noise; is another name for Brown Noise, and an oceanographic term which
describes the ambient noise of distant underwater objects due to the selective
absorption of higher frequencies. The color "Red" refers to the loss of higher
frequencies with an emphasis on lower frequencies (this is from the White
Noise/White Light analogy and applies to either of the above definitions).
White Noise; a random noise that contains an equal amount of energy in all
frequency bands. White Noise is the equivalent of White Light and is how it gets
its name. White Light is made-up of all light frequencies (colors), while White
Noise is made-up of all audio frequencies. White Noise is used in electronic
music, either directly as a sound effect or as the basis to create other noises. For
example, many percussion instruments have a high component of White Noise.
White Noise is also used to mask other sounds. This process takes advantage of
the way the human brain works; the brain is able to single-out simple frequency
ranges but has trouble when too many frequencies are heard at once. When
White Noise is present, other noises appear diminished.