What is pink noise?


What is pink noise? I want to know about pink noise. I make a request.
bluesky

Showing 5 responses by alcides

Pink noise is equal energy at any given octave. White noise is equal energy at any given frequency.

The result is that white noise sounds more like high frequency noise, and pink noise sounds like full range noise.

Think of it this way. An octave represents a doubling of frequency (40Hz is an octave higher than 20Hz. 14,000Hz is an octave higher than 7000Hz etc.)

As you look at that, think about how many more frequencies are contained within any given octave as you go up the musical scale.

Concert A (a minor third below middle C on the piano) is equal to 440Hz. The lowest note on the piano (excluding some Bosendorfers) is three octaves below that, or 55Hz. If we count in whole integers, there are only 385 frequencies between those three octaves. Three octaves ABOVE concert A resonates at 3,520Hz. If we count in whole integers again, there are 3080 frequencies between concert A, and the A three octaves above it.

If each one of the 3,465 frequencies implied in the above paragraph has the same power when they are all played at once, we will hear the higher frequencies as being louder, because there are more of them per any given octave as you go up the scale. White noise

If you devide up those frequencies into octaves, and compensate for the doubling of energy that is inhearant in white noise by giving as much energy to the octave between the lowest note of the piano ((A1-A2) 55-110Hz) as you would to the higest octave of the piano ((C7-C8) 2093.04 - 4186.08Hz,) you get Pink Noise.

hope this helps
the name pink noise comes from the fact that the noise is skewed with more power towards the low frequencies... i.e. the redish or pink equivelant in the visual spectrum.

White light has equal energy per frequency as well.
Cdc,
If you must use a broadband noise signal, use pink noise. White noise will be irrelevant. If you use a broadband noise signal like pink noise, you need to have a spectum analyzer to really be able to measure the in room response. These will generaly give you a graphic display with frequency on the x axis, and absolute level on the y axis. Much like the graphs we all see in Stereophile etc. Measurments of this type get tricky and expensive.

Stereophile's discs do miss much of the spectrum, but what they include are tones that actually apply to areas in your listening room that you might actually have realistic control over. They also assume the average listener is going to have a radio shack SPL meter that has poor frequency response in the low and high end.