Wednesday, October 21, 2009

Probability of a Fax Machine

A pitch modulating circuit using a s/h waveform lfo. Generates a variety of sounds from subtle pitch variation to total poop digital breakdown.

Controls:

Period: This knob controls the period of the s/h wave form. (Essentially the speed or rate of the LFO).

Mix: This allows you to blend the clean sound going into the pedal with the effected sound coming out of the pedal. One extreme => just clean, the other extreme => just effected signal.

Volume: A master output level control.

Mean: The end result of this knob is not simply explained and its result is highly interactive with the skew knob. It will affect several things sonically. At min the effect will be subtle and the sound quality will be quite high. As the knob is rotated the probability of glitchy sounds will increase, however their will be some headroom where quite normal sounding tones will be produced.


Skew: This knob is interactive with the mean knob. It will in effect control the variation of pitches that is produced. However this range is also somewhat controlled by mean. An example: Mean somewhere in teh middle and skew quite low will result in just small pitch variations. With skew increased the pitch variation between the output tones will be more varied.

The best way to get a feel for what these knobs do is to watch the sample videos...


video

video

sample with clean guitar here

joy

My friend asked me to make something like this for him.

What it is:

More or less a mixer of 2 effect loops. One loop has the volume control at the effect send and one loop has the volume control after the return. The x-axis of the stick controls one loop and y-axis the other.

Also each channel can be subjected to a feedback loop, which makes it behave a bit like the "total sonic annihilation" pedal (per loop).






Tuesday, October 20, 2009

red llama clone

This is the last of the left over boards from a workshop long ago... Built for a friend. Its sort of a mix between the anderton hexfuzz and the red llama. I think the red llama doesn't actually have the additional overdrive switch, but it uses different 'tone' caps than the hexfuzz.

This is sort of the best of both worlds with the switch implemented in stop form and a red/green led to indicate which mode your in.

From the waves you can see the regular overdrive is asymmetrical and a bit soft. IT sounds not bad. People seem to like it.

Heres the led... one button is bypass and one is the 'mode' of the overdrive... knobs are volume and gain.

video


Heres a look at the signal... order is something like clean, low gain, play with gain knob, play with volume knob, change to high gain/low gain/off etc...

video

Tuesday, April 28, 2009

Tuesday, February 10, 2009

general myron

Sunday, February 1, 2009

more generation of random frequencies

one day ill have a camera with video and sound. in the meantime....

video

Saturday, January 31, 2009

higher frequency content



relative polytone generator. excessive use of precision rectification op amp circuits. wont be perfect due to wave shape but should "work". (f, oct, oct+p5, 2nd oct, etc...).



sine wave through 4 folds. dramatization of new "high frequency content".

f(x) = sin(2x)
g(x) = 2|f(x)| - 1
j(x) = 2|g(x)| - 1
k(x) = 2|j(x)| - 1, etc...

|f(x)| implemented through rectification. -1 or -c (a constant) represents a DC offset, without which running stages in series would be ineffective.



it isn't a strict doubling of frequency, but an approximation of. the shape of f(x) will change unless it is a perfect triangle. but that might be the charm of it. ie the harmonics generated will be waveform dependant, although there should be general trends.


using FFT approximation to see spectrum created...

first fold shows strong second harmonic, subsequent folds show a reasonable fourth then a fair distribution of upper even harmonics.






from this point high pass filters could be used with a sort of subtractive synthesis mentality to move the distribution more in favor of the higher ordered harmonics. not sure if 6 stages are really necessary. probably 4 would be interesting enough.

Friday, January 30, 2009

beyond 2000, one bit multiplier



block diagram for a more complete implementation of "what we thought the year 2000 would sound like". program selectable lfo and harmonics filter to alleviate "generic" restructuring of any input and other problems.

possibly will be asm three/four etc...

isd interchange




relaxed implementation of chopping/sampling ideas. burdens and limitations of isd smoothed over by flexible connections with acoustically distracting hardware.

project proposed in conjunction with emilie mouchous.

Thursday, January 1, 2009

tribute to 2009

a somewhat deterministic signal volunteers itself to the consequences of a randomly controled system.

s/h to the mouchous

video

random signals...


Zener Type Avalanche Noise Generation:

"Matthew J Bennion, mjb296@soton.ac.uk, pointed out that noise sources are important as random number generators, for situations where you really do need truly random numbers (as opposed to the pseudorandom number generators implemented in software). An example where this is necessary might be encryption and decryption"

"I agree with what you have on Noise Diodes, but I think you overlook the main use: measurement of noise figure. To characterize, for example, a receiver, one adds noise from a noise generator until the observed noise just doubles (or changes by some other convenient factor). Shannon's theorem says that noise always adds (Murphy's law says the same thing). Since the noise generator would typically make a relatively high level of noise that would be attenuated down by precicesly calibrated attenuators, one can know how much noise was required to equal the intrinsic noise of the receiver, and thus infer its performance."

"This white noise generator is based on the avalanche noise generated by a zener breakdown phenomenon. It is created when a PN junction is operated in the reverse breakdown mode. The avalanche noise is very similar to shot noise, but much more intense and has a flat frequency spectrum (white). The magnitude of the noise is difficult to predict due to its dependence on the materials."

Shot Noise Generation:

"Shot noise exists because phenomena such as light and electrical current consist of the movement of discrete, quantized 'packets'. Imagine light coming out of a laser pointer and hitting a wall. That light comes in small packets, or photons. When the spot is bright enough to see, there are many billions of light photons that hit the wall per second. Now, imagine turning down the laser brightness until the laser is almost off. Then, only a few photons hit the wall every second. But the fundamental physical processes that govern light emission say that these photons are emitted from the laser at random times. So if the average number of photons that hit the wall each second is 5, some seconds when you measure you will find 2 photons, and some 10 photons. These fluctuations are shot noise."

The full picture/recent developements and changes in thinking...

http://www.lorentz.leidenuniv.nl/beenakkr/mesoscopics/topics/noise/noise.html


The Poisson Distribution:

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



sources:

http://www.maxim-ic.com/appnotes.cfm/an_pk/3469
http://www.avtechpulse.com/faq.html/IV.8/
http://en.wikipedia.org/wiki/Shot_noise