I'm looking to build myself a noise box that generates these kinds of crunchy sounds. But I don't even know what to call them in order to research it. Would anyone know what they are?
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Toronto, Ontario, Canada
It's just very high frequency sudo white noise. White noise on a computer is never truly random, therefor there is a repeating cycle. At very high frequencies these repeating cycles form tonal sounds.
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Gosford, Australia
pretty much what jeff said. the pseudo-whitenoise in a gameboy is made with an algorithm called a linear-feedback shift register.
http://gbdev.gg8.se/wiki/articles/Gameb … se_Channel
http://www.belogic.com/gba/channel4.shtml
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Katowice, Poland
White noise on a computer is never truly random, therefor there is a repeating cycle
You wanted to say: there is a repeating cycle, therefore white noise on a computer is never truly random? 
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Toronto, Ontario, Canada
Jakim wrote:
White noise on a computer is never truly random, therefor there is a repeating cycle
You wanted to say: there is a repeating cycle, therefore white noise on a computer is never truly random?
Well, no. The repeating cycle is an effect of the computer's inability to be random. Not the other way around. The root cause is the PRNG. Since computers are deterministic, they can't simply "be random". There are various tricks used to get random-ish numbers, though. However, the gameboy (and all z80 devices) has a very poor PRNG, indeed. It's not bad because it repeats, it repeats because it's bad.
(I think what you wanted to say was: Really, the sentence works either way.)
Last edited by jefftheworld (Aug 23, 2013 7:02 am)
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Katowice, Poland
I was thinking about abstract categories. Your implication is false, there are objects which aren't random but without period neither, see for example geometric progression. But there is no random object with period. You have to notice/assume something more to put an equivalence to these statements. Perhaps you was talking about common general rule, where I could agree.
Computer's inability to be random you have stated isn't an immanent property.
Greetings.
Last edited by Jakim (Aug 23, 2013 7:27 am)
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Sweeeeeeden
Something like a geometric progression only lacks cycles because it is theoretically infinite. The reason why a PRNG will repeat is because it's contained in a finite state machine, and it will eventually (in isolation) reach a previous state and start over. For a digital (binary) machine, this is an imminent property -- it is a finite state machine by design, unless it's working poorly or takes aid from non-digital components or random memory state at startup. The state can be made arbitrarily big today, however.
And this is where the practical aspect comes in. It's possible to design a PRNG which is so good that it will never practically repeat within the age of the universe, and will pass any randomness test you can come up with. Obviously, you still need to seed it with "real" randomness to get a properly random stream of numbers, but even a zero initial state of a good PRNG will pass randomness tests done blind, ie without expecting that articular PRNG:
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Katowice, Poland
(...) because it is theoretically infinite.
That's why I've marked I was talking (writing) about abstract categories.
this is an imminent property -- it is a finite state machine
Right! But you've chosen a bit different property, the inability to be random is a nonimmanent consequence of it (and some other properties). I agree about practical details you have mentioned.
Last edited by Jakim (Aug 23, 2013 8:19 am)
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Boise, ID
Hm... Thanks for all this feedback, but I suppose a better question to ask would have been: how can I "sweep" the pseudo white noise the same way a gameboy does? Have any of you ever built something modular to do this?
Also is this what I'm looking for? http://www.nutsvolts.com/uploads/magazi … erator.pdf
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Michigan
I like the idea of a tuneable white noise generator. It requires a white noise input though...
Little-scale has written some nice stuff about EEPROM music, so I suggest you have a read:
http://www.little-scale.blogspot.com.au … om%20music
I can imagine using a serial eeprom with 2kbits of storage and a pic chip of sorts to have it spit out your 4-bit+ sample. Cheap as all hell, but may require some work and programming on your end. Once you got that worked out, you could then feed it into your tuner as posted above.
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I thought the minute you tune white noise it ceases to be white noise. Pink or brown?
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Michigan
herr_prof wrote:
I thought the minute you tune white noise it ceases to be white noise. Pink or brown?
lol....right. 
Noise spectrum changer, more like?
EDIT: Grey noise is prettiest. 
http://en.wikipedia.org/wiki/Colors_of_noise
Last edited by Jazzmarazz (Aug 23, 2013 5:50 pm)
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Acoustic Test Signal Generators have that kind of ability so I guess, Sweepable Noise Generator? Trash80 made a really nice gameboy papu-eque noise generator in his digitek esemble:
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Sweeeeeeden
If you're looking for something computer-ey, and you have Reaktor, this might be of interest.
http://veqtor.blogspot.se/2008/10/meet-bitfreak.html
YMCK's magical 8bit plug may be able to do it as well.
http://www.ymck.net/en/download/magical8bitplug/
If you mean modular as in analog modular synth, you could buy a Zorlon Cannon. Or build something on your own. From a quick google, say this or this:
http://www.sailormouth.org/fuzprng.html
http://jaunty-electronics.com/blog/2012 … ator-prng/
Just add a voltage controllable squarewave generator.
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Tacoma WA
Cool Thomas Henry link
For eurorack zorlon cannon and maybe hex invertors Jupiter Storm
http://cv.hexinverter.net/?projects=jup … ack-module
Reading the description of the sounds from that link something like the hertz donut mk2 would work as well, seems like the big thing it's doing is fming rather than filtering
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FRANCE
Might not be 100% LFSR only related but I will release my SN76489 (sega master system version) Vsti extended emulation in September...
The Super Portable Sound Generator aka Supa PSG.
One of the feature is the ability to tweak the noise channel
More technically you will be able to change the 16bit LFSR configuration in real time.
Changing the tapped bits and the feedback bit input can make the noise more or less tonal like switching between SN79489, Atari2600 etc..Noise types
that type of sound you give in your example is totally achievable.
Worth mentioning that the master clock of the system is not particularly tied to PAL or NTSC and can be set(also in realtime) from 1 to 4Mhz.