Specifications

EAW Smaart 6 Operation Manual Concepts, Glossary, and Bibliography
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2.1.6 Pink and White Noise
Pink and white noise both contain random (or pseudorandom) broadband energy. They
are commonly used as signal sources in audio measurement applications.
Pink Noise
Pink Noise has equal energy in each octave band when averaged over a period of time.
This means that when pink noise is displayed on an octave band plot, its spectrum appears
flat. When its spectrum is plotted on a narrowband display, however, it appears to roll-
off, or decrease in energy at the rate of -3 dB per octave (Figure 2-1).
Figure 2-1 Pink noise graphed on octave band (left) and narrowband logarithmic (right) scales
White Noise
White noise has equal energy for each frequency when averaged over a period of time.
This means that when white noise is displayed in narrowband resolution, its spectrum
appears flat. However, because each successive octave band has twice as many Hz,
white noise plotted on an octave band display appears to increase 3 dB in energy for
each successive octave (Figure 2-2).
Figure 2-2 White noise graphed on octave band (left) and narrowband logarithmic (right) scales
–30
–20
–40
–50
–60
–70
32 63 125 250 500
Frequency (Hertz)
Octave Scale
Decibels
1K 2K 4K 8K 16K
Frequency (Hertz)
Logarithmic Scale
(Narrow Band)
Decibels
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–20
–40
–50
–60
–70
20 100 1K 10K 22K
Logarithmic Scale
(Narrow Band)
Decibels
–30
–20
–40
–50
–60
–70
20 100 1K 10K 22K
–30
–20
–40
–50
–60
–70
32 63 125 250 500
Octave Scale
Decibels
1K 2K 4K 8K 16K