what the hell is white/pink noise?

[hubb]

what the is this white/pink noise thing i keep hearing and how do you make or generate it? what's it used for?

[Serj]

Why all the questions? White noise is basically sounds like static on a TV ("rice" or "snow") It is a sound that is unpleasant and avoided. As for pink noise, I don't think there is such a thing, unless you were just trying to be clever.

[cstime]

The guide for goobers defines it as:

 

Pink Noise: A type of audio signal used for measurement and analysis. Pink noise is derived from white noise (all frequencies in the human hearing range at equal amplitude), by filtering it to attenuate the volume of the signal at a rate of 6dB per octave. This compensates for the doubling of the number of frequencies per ascending octave. This produces a signal which has equal energy at every octave.

[hubb]

 

Why all the questions? White noise is basically sounds like static on a TV ("rice" or "snow") It is a sound that is unpleasant and avoided. As for pink noise, I don't think there is such a thing, unless you were just trying to be clever.

 

 

just trying to get stuff figured out.

 

i've the terms white noise and pink noise and from what i've read there is a difference. a guy i know keeps telling me to run sound properly you should "eq the room with white noise" i don't know what this means or how you would do it.

[ashivraj]

if you dont know what it is, there's a good chance yuo wont know how to do it.

 

you'd usually EQ a room by running pink noise through the speakers, then using a room calibration microphone - or several - to pick up what's coming out, and show it to you graphically, either with an analog RTA (lots of LEDs) or a digital one (computer-based, or at least, with an LCD display). so the pink noise would be a flat line, but what the room mic(s) pick up will rarely be a flat line. then, you tweak your EQs to adjust for the characteristics of the room (and the speakers), and what you end up with is an almost transparent sytem... signal in = signal out, with hardly any coloration, some times none at all.

 

of course, with even the best of systems, GIGO applies. a crappy band - or any crappy input signal - will come out crappy. can't do much about that.

 

AS

[Craig Vecchione]

Just for info, white noise sounds like TV-no-signal static, and pink sounds more like a waterfall due to its full-spectrum of sound.

[fossil]

Plucked from the internet by doing a search for "Pink noise definition":

 

white noise

 

White noise is a sound that contains every frequency within the range of human hearing (generally from 20 hertz to 20 kHz) in equal amounts. Most people perceive this sound as having more high-frequency content than low, but this is not the case. This perception occurs because each successive octave has twice as many frequencies as the one preceding it. For example, from 100 Hz to 200 Hz, there are one hundred discrete frequencies. In the next octave (from 200 Hz to 400 Hz), there are two hundred frequencies.

White noise can be generated on a sound synthesizer. Sound designers can use this sound, with some processing and filtering, to create a multitude of effects such as wind, surf, space whooshes, and rumbles.

 

Pink noise is a variant of white noise. Pink noise is white noise that has been filtered to reduce the volume at each octave. This is done to compensate for the increase in the number of frequencies per octave. Each octave is reduced by 6 decibels, resulting in a noise sound wave that has equal energy at every octave.

[Black Frog]

White noise has the same distribution of power for all frequencies, so there is the same amount of power between 0 and 500 Hz, 500 and 1,000 Hz or 20,000 and 20,500 Hz.

 

Pink noise has the same distribution of power for each octave, so the power between 0.5 Hz and 1 Hz is the same as between 5,000 Hz and 10,000 Hz. The amplitude reduction per octave as stated before is done to compensate for the increase in the number of frequencies per octave. Gotta keep things level across the spectrum.

 

[Mudbass]

 

Originally posted by ashivraj if you dont know what it is, there's a good chance yuo wont know how to do it. you'd usually EQ a room by running pink noise through the speakers, then using a room calibration microphone - or several - to pick up what's coming out, and show it to you graphically, either with an analog RTA (lots of LEDs) or a digital one (computer-based, or at least, with an LCD display). so the pink noise would be a flat line, but what the room mic(s) pick up will rarely be a flat line. then, you tweak your EQs to adjust for the characteristics of the room (and the speakers), and what you end up with is an almost transparent sytem... signal in = signal out, with hardly any coloration, some times none at all. AS

 

 

 

...and then the room fills up with people and the whole EQ curve changes.

[Durwood]

In the cases that I have used pink noise I have always "tweeked" the system after I was done...When a system is totaly "flat" it doesn't sound right to our ears a lot of times...there is no excitment..however I have found the times that I have had a chance to pink noise the room has made the over all sound better when mixing. Pink noise is used in Recording to set up a studio so that the sound is not colored from the speakers or the room...by doing this it is easier to make a cd sound good from one place to another...

[mrcpro]

 

Originally posted by ashivraj if you dont know what it is, there's a good chance yuo wont know how to do it.

 

 

Well, I use white noise for tishy hi-hats and pink noise for 808 snares, but that's the synth programmer in me;) .

[agedhorse]

 

Originally posted by Black Frog White noise has the same distribution of power for all frequencies, so there is the same amount of power between 0 and 500 Hz, 500 and 1,000 Hz or 20,000 and 20,500 Hz. Pink noise has the same distribution of power for each octave, so the power between 0.5 Hz and 1 Hz is the same as between 5,000 Hz and 10,000 Hz. The amplitude reduction per octave as stated before is done to compensate for the increase in the number of frequencies per octave. Gotta keep things level across the spectrum.

 

This goes back a ways, but this explaination may help with the concept.

 

White noise has the same power amplitude at each discrete frequency, while pink noise has a power amplitude that decreases at a rate of 3dB (power) per octave.

 

Since a real time analyzer integrates each octave's worth of power, and the octaves have increasing frequency bandwidth as the frequency increases, the incrimental power must be reduced in order to compensate for the increased bandwidth.

 

This is the same principles that are used when designing speaker crossovers and voicecoils, since power bandwidth must factor both power and bandwidth in order to determine the system (and individual driver) power handling.

[RickJ]

 

Durwood wrote: In the cases that I have used pink noise I have always "tweeked" the system after I was done...When a system is totaly "flat" it doesn't sound right to our ears

 

I'm sorry to disagree with you. Your ear is no match for electronic calibration. There should be no need to tweak the FOH EQ if you've already calibrated it to as flat as it can be.

 

A flat (and loud and clean) speaker system will bring out all of the subtleties of the instruments if they sound good to begin with.

 

I rarely, if ever, have a channel strip EQ with more than +/-3dB of deviation if the speakers are flat and the instruments are properly tuned. The instruments naturally blend with each other, so on a flat system it's primarily a matter of mixing loudness first instead of grabbing an EQ knob.

 

Then again, I normally don't have to worry about insufficient or inefficient speaker systems. If you're tweaking after the fact, you need better speakers.

[agedhorse]

 

Originally posted by RickJ I'm sorry to disagree with you. Your ear is no match for electronic calibration. There should be no need to tweak the FOH EQ if you've already calibrated it to as flat as it can be. A flat (and loud and clean) speaker system will bring out all of the subtleties of the instruments if they sound good to begin with. I rarely, if ever, have a channel strip EQ with more than +/-3dB of deviation if the speakers are flat and the instruments are properly tuned . The instruments naturally blend with each other, so on a flat system it's primarily a matter of mixing loudness first instead of grabbing an EQ knob. Then again, I normally don't have to worry about insufficient or inefficient speaker systems. If you're tweaking after the fact, you need better speakers.

 

I couldn't agree more. THIS is the formula for being successful as a sound engineer... having the right tools and knowing how to use them correctly. When done correctly (as in not over-eqing, or trying to fix something that can't be fixed with an eq) it will make the task of mixing easier.

 

It is easy to mis-use an RTA, either by not averaging readings over several parts of the listening area or trying to equalize a time domain problem (build-up or cancellation due to reflections from room geometry or sometimes speaker placement) in the frequency domain (eq).