hey guys,





i just posted this in another thread, but it will obviously get more attention here...





bit of a technical one,





i just got the new chesky records best 10 off marc on sunday,



it containde a track which was all pink noise,



as annoying as this noise is, i know its used to tune for SQ somehow,





would anyone care to enlighten me, as i would like to try...





cheers

charlie

used in conjunction with a db meter (the rough way to do it) or with something more accurate like a termlab...pink noise means there is equal energy in each octave.
so to play pink noise on a perfect (technically) system, when looking at the frequency response using a termlab (or db meter), the response would be flat across the frequency spectrum (20hz-20khz)...now its pretty hard to get speakers to play 20hz and 20khz as easily as they do the frequencies in between, so generally you would see some fall off at these extremes.

^^^ What Spyne said. Can also use an RTA if you have access to one. Its to judge how flat your response is.

also see my thread 'how pink is your noise'

http://www.caraudioaustralia.com/forums/in...pink+your+noise

i belive when you are on acid is looks pink :\

whats white noise?

This is

White noise has an equal amount of energy for every frequency.



Pink noise has an equal amount of energy per octave

"White noise has an equal amount of energy for every frequency.
Pink noise has an equal amount of energy per octave".

Call me stupid, but isn't that the same thing????

If each octave has the same energy as all the others, wouldnt every frequency in each ocatve also contain the same energy, therefore making all frequencies in each octave contain the same energy?

Yeah I'm probably wrong, but please enlighten me on the difference.

Pink Noise = All frequencys at equal levels. {Most common from 10Hz to 40KHz}
Use pink noise with a RTA to get a visual representation of the systems frequency response.
Has FA to do with octaves.
White Noise = All frerquencys at unequal levels. Useless for tuning. If you want to hear white noise tune your radio to a station that doesn't exist.
Cheers

i agree with proclass...

say i have a silent room, and have a oscillating air mover, and turn it on, that will be white noise....

Id hate to be an ar$ehole here, but Im correct. Pink noise is equal energy per OCTAVE. Each octave contains twice as many frequencies as the one before it (ie. 100 to 200 Hz has 100 frequency bands, whilst 200 to 400Hz has 200 frequency bands). Therefore, as you go up in the octaves, white noise gives the 'perception' of getting louder because its equal energy per frequency (and therefore its level doubles every octave).

Pink noise has an attenuation to it, so for every octave up, it halves its energy. This gives equal energy per octave, but half the energy per frequency as the frequency in the octave below it.

There also exists Brown Noise and Blue noise.

I dont know about you, but i find pink noise to be great for centre imaging pa setups. Stand in the sweet spot, get someone to slowly pan left, to centre, then to right, and you'll spot straight away if theres a phasing issue.

hmmmmm....

how much are RTA's????

is thier a cheper way to do this???

i mean to graph frequency responce??

can i borrow someones golden ears???

Pink Noise
"There is equal energy in all octaves. In terms of power at a constant bandwidth, 1/f noise falls off at 3 dB per octave."
Have a read.
http://en.wikipedia.org/wiki/Pink_noise

An RTA was a standard piece of equipment in any quality audio shop. I have one. Not the best money can buy but accurate enough for my purposes. About $800.00

Cheers

and proclass u have just corrected urself...as previously stated, pink noise is equal energy per octave, which is DIFFERENT to white noise (equal energy per frequency)

So then whats blue noise and brown noise?

Is brown noise what i think it is..... as is... passing of gas....


I hope not.....

This describes all the colours better then I can, at least understandably.

http://en.wikipedia.org/wiki/Colors_of_noise

Before reading this though, I wasnt aware of purple and grey. You learn something new everyday!!

yeah i read thru that a couple months ago, its pretty informative.....

brown noise isnt what most ppl think it is ie the whole mythbusters or whatever.....that was just to see if low frequencies could create movements in a specific internal organ, thus brown noise

Every bloody day!
Thanks Matt!

mmmmmmmm, purple noise.

lol

Be careful using purple noise. You might mistake it for those nasty nasty black ones. Urgh.....

sorry, wrong thread

Audicontrol, Coustic and Termlab all have options for RTA attachments that will measure Pink nopise and it can be usefull for tunning.

My termlab RTA upgrade has been a handy little tool and a few dealers in Melb have audicontrol or Coustic meters.