Different in noise. Can someone explain pls?

Autobot
 KVRian
 718 posts since 27 Mar, 2013
Different in noise. Can someone explain pls?
I'm aware of the different colors of nice like brown, pink, white, etc. noise but what exactly is Gaussian, FF21/F2, Crackle, Dust, Bow, MM5837, LFClipNoise, Logistic, LorenzRossler, Wave, etc. noise?
I found a Max4Live device (http://maxforlive.com/library/device/4588/fpnoise) with those different types of noise and wonder whats about. Can those type of noises reproduce with a synth like Zebra or similar.
Someone here to share knowledge? Thanks.
I found a Max4Live device (http://maxforlive.com/library/device/4588/fpnoise) with those different types of noise and wonder whats about. Can those type of noises reproduce with a synth like Zebra or similar.
Someone here to share knowledge? Thanks.
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BertKoor
 KVRAF
 11832 posts since 8 Mar, 2005 from Utrecht, Holland
Re: Different in noise. Can someone explain pls?
You could do some googling and find:Autobot wrote: ↑Tue Mar 31, 2020 6:02 amI'm aware of the different colors of nice like brown, pink, white, etc. noise but what exactly is Gaussian, FF21/F2, Crackle, Dust, Bow, MM5837, LFClipNoise, Logistic, LorenzRossler, Wave, etc. noise?
I found a Max4Live device (http://maxforlive.com/library/device/4588/fpnoise) with those different types of noise and wonder whats about.
https://en.wikipedia.org/wiki/Gaussian_noise
https://www.musicdsp.org/en/latest/Synt ... ators.html
http://synton.nl/wpcontent/uploads/2017/04/mm5837.pdf
So most of these types are about the calculational model used to generate it. Just run it and take a look at the spectrum it generates.
So that's "no, not directly"uhe Zebra product page wrote: The Noise module features four different flavours: White, Pink, Digital, and Crackles  which produces sounds simlar to a Geiger counter
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Autobot
 KVRian
 718 posts since 27 Mar, 2013
Re: Different in noise. Can someone explain pls?
Thanks. I used google but since I'm not a scientist the explanations did not brought me further I would be more interested in the sound of the different noises. As I said I'm familiar with different colors of noise and their sound but how does sound MM5837 noise? As far as I understand the MM5837 is a chip for generating pink/white noise. So whats the difference in terms of sound?
Edit: maybe I buy the m4l device to test the sounds by myself. although for the 3€ I could buy groceries for a little dinner. Yes! I'm tight on money...
Edit: maybe I buy the m4l device to test the sounds by myself. although for the 3€ I could buy groceries for a little dinner. Yes! I'm tight on money...
Last edited by Autobot on Tue Mar 31, 2020 6:29 am, edited 1 time in total.
I grew up on a junkyard, where I started to feed from hubcaps and bumpers

Autobot
 KVRian
 718 posts since 27 Mar, 2013
Re: Different in noise. Can someone explain pls?
sorry. double post.
I grew up on a junkyard, where I started to feed from hubcaps and bumpers

andro_b
 KVRer
 5 posts since 21 Feb, 2020
Re: Different in noise. Can someone explain pls?
Take a look at Dr. Stéphane Pigeon's page of audio tests, in particular here:
https://www.audiocheck.net/testtones_index.php
He gives some subjective impressions and perceptions of what different 'colours' of noise sound like, and an explanation of each term.
It is indeed a mathematical subject, but the above has good verbal descriptions, and sound samples.
Things like crackle and dust are not mathematical noises, but usually based on csound generators which model those phenomena, using algorithms to emulate such things. Various synths have varying numbers of different types of noise, but usually white and pink at a minumum. If you want lots of noise generators, the software (and hardware) modular synths have hundreds of noise modules available.
https://www.audiocheck.net/testtones_index.php
He gives some subjective impressions and perceptions of what different 'colours' of noise sound like, and an explanation of each term.
It is indeed a mathematical subject, but the above has good verbal descriptions, and sound samples.
Things like crackle and dust are not mathematical noises, but usually based on csound generators which model those phenomena, using algorithms to emulate such things. Various synths have varying numbers of different types of noise, but usually white and pink at a minumum. If you want lots of noise generators, the software (and hardware) modular synths have hundreds of noise modules available.

mystran
 KVRAF
 5651 posts since 12 Feb, 2006 from Helsinki, Finland
Re: Different in noise. Can someone explain pls?
It is also possible to imlement such thing as simple samples, looped and started from a random position (just make them long enough that the repeat isn't obvious), or you could even do some sort of granular synthesis for them. This way you can easily have "noise generators" that produce sounds that are tricky and/or expensive to model properly.
Another classic approach to generating "standard" noise with arbitrary spectrum is to take a long FFT window (eg. at least 1015 seconds), fill the magnitudes with whatever spectrum you want, randomize the phases and then IFFT the thing to get a perfectly looped sample.
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Music Engineer
 KVRAF
 3834 posts since 8 Mar, 2004 from Berlin, Germany
Re: Different in noise. Can someone explain pls?
if you read something like "gaussian", this refers to the probability density distribution of the noise  that is the relative number of samples that fall in a given range of amplitude values. the most basic noise generators will give you a uniform distribution of the amplitude values. to see this, you want to look at the histogram. for uniform noise, it looks like this:
every amplitude value is equally likely to occur. if you add the output of two such uniform noise generators (and divide by two), you get a triangular distribution like this:
and if you add the output of three (and divide by 3), you get this:
this is actually a piecewise parabolic curve. if you add n noise generators, the theoretic shape is the convolution of n rectangular functions which gives you a piecewise (n1)th order polynomial. the next one would be piecewise cubic, etc. and the shapes become more and more gaussian'ish, the more noisegenerators you add. this is called the IrwinHall distribution. note that all these noises are spectrally white  and also sound more or less the same to me (although, of course, the uniform is loudest because it has the highest amount of highamplitude values) but the distribution of amplitude values may likely have effects on nonlinear processors further down the signal chain (just a hunch  i did not yet explore this very much).
every amplitude value is equally likely to occur. if you add the output of two such uniform noise generators (and divide by two), you get a triangular distribution like this:
and if you add the output of three (and divide by 3), you get this:
this is actually a piecewise parabolic curve. if you add n noise generators, the theoretic shape is the convolution of n rectangular functions which gives you a piecewise (n1)th order polynomial. the next one would be piecewise cubic, etc. and the shapes become more and more gaussian'ish, the more noisegenerators you add. this is called the IrwinHall distribution. note that all these noises are spectrally white  and also sound more or less the same to me (although, of course, the uniform is loudest because it has the highest amount of highamplitude values) but the distribution of amplitude values may likely have effects on nonlinear processors further down the signal chain (just a hunch  i did not yet explore this very much).
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Music Engineer
 KVRAF
 3834 posts since 8 Mar, 2004 from Berlin, Germany
Re: Different in noise. Can someone explain pls?
just a few days ago, i played around a little bit with combining basic noise generators. here is an example of some sort of crackly noise (i needed to zip it because the forum does not support wavefile attachments):
it has 3 maxima, which is why i called it trimodal. but the histogram does not tell you the full story  i could create noises with the same distribution without the lowpass on the selector but they would sound totally different  the crackle would be gone. note also that the frequency spectrum also doesn't really tell you very much here  it looks almost white, too with a slight boost of lower frequencies. i wonder which sort of plot would reveal the features of this sort of noise. maybe some sort of histogram that shows the conditional probability of amplitude values, conditioned on what the previous value was  or something. i guess, if one likes noises, one can have a lot of fun by combining noise generators in various ways
what i did here was the following: use three irwinhall generators (of order 7) with different centers (one in the middle, i.e. mean=0, one with negative and one with positive mean), use another noise generator to select, per sample, which one of the three to use for the current sample. the selector generator is lowpassed in order to make it more likely to select the same from the 3 for successive samples. the result is some sort of crackle. this noise has the following distribution:it has 3 maxima, which is why i called it trimodal. but the histogram does not tell you the full story  i could create noises with the same distribution without the lowpass on the selector but they would sound totally different  the crackle would be gone. note also that the frequency spectrum also doesn't really tell you very much here  it looks almost white, too with a slight boost of lower frequencies. i wonder which sort of plot would reveal the features of this sort of noise. maybe some sort of histogram that shows the conditional probability of amplitude values, conditioned on what the previous value was  or something. i guess, if one likes noises, one can have a lot of fun by combining noise generators in various ways
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Music Engineer
 KVRAF
 3834 posts since 8 Mar, 2004 from Berlin, Germany
Re: Different in noise. Can someone explain pls?
lorenz and rössler systems are a totally different thing. they are based on chaotic systems of differential equations:
https://en.wikipedia.org/wiki/Lorenz_system
https://en.wikipedia.org/wiki/R%C3%B6ssler_attractor
lorenz sounds like this:
maybe not totally useless. physics is full of such chaotic systems. might be fun to explore. i didn't do rössler yet, but i can serve with doublependulum instead:
https://en.wikipedia.org/wiki/Lorenz_system
https://en.wikipedia.org/wiki/R%C3%B6ssler_attractor
lorenz sounds like this:
maybe not totally useless. physics is full of such chaotic systems. might be fun to explore. i didn't do rössler yet, but i can serve with doublependulum instead:
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BlitBit
 KVRist
 320 posts since 28 Nov, 2013 from Germany
Re: Different in noise. Can someone explain pls?
First of all, thanks for this great visual explanation! Do I understand correctly that this basically means: If you take two white noise sources and mix and normalize them then it will be more likely that two mixed samples will cancel out than that they result in a "large" value?Music Engineer wrote: ↑Sat May 23, 2020 8:21 amevery amplitude value is equally likely to occur. if you add the output of two such uniform noise generators (and divide by two), you get a triangular distribution like this:
NoiseTriangular.png
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Music Engineer
 KVRAF
 3834 posts since 8 Mar, 2004 from Berlin, Germany
Re: Different in noise. Can someone explain pls?
yes, indeed.If you take two white noise sources and mix and normalize them then it will be more likely that two mixed samples will cancel out than that they result in a "large" value?