Author |
Message |
EATyourGuitar
Joined: Oct 28, 2010 Posts: 59 Location: Providence, RI
|
Posted: Sun Oct 14, 2012 7:45 am Post subject:
XOR chain + VCLFO = VC noise |
|
|
I made two important discoveries with 16 square LFO's feeding a cascading XOR chain. the order of the inputs and the exact schematic of the XOR chain is not important since you can apply the communicative properties of multiplication -1*x=(-1)*x
as the title of this thread suggests, you can achieve voltage controlled noise. on an FFT you will see a resonant band that moves up or down in frequency as you increase or decrease CV to your LFO's. the LFO's can be any frequency as long as the frequency of the LFO's increases proportional to the LFO rate CV also increasing. while the resulting output of the XOR chain has no fixed frequency, it does have an average rate of zero crossings per second (the resonant band) that can be controlled by controlling the rate of the LFO's with a common CV signal.
the second discovery has less to do with VC noise and more to do with a noise sequencer capable of making complex repeating patterns using only 16 LFO's feeding into the XOR chain. VC over the LFO's is not required here but a sync input for each LFO is required. tune each LFO to an arbitrary frequency. sync 15 of your 16 LFO's to LFO 1. LFO 1 has nothing connected to the sync input so it will be the master clock acting as a reset for a sequencer who's length is infinite. there you have a 1 bit pattern that can be sync'd to any other gear. you could even clock it with more musical gear. optionally, you can insert clock dividers of /2 and /4 before any of the sync inputs to increase the length of the pattern while also decreasing the Q of the resonant frequency band.
I have not tried feeding a serial DAC but you could probably do it. with a serial clock divided by 8 running to your sync inputs on the LFO's. this would give you an arbitrary waveform generator that is driven from your serial clock or any other VCO in your system. you could generate upper and lower harmonics to your VCO without being stuck in square waves. |
|
Back to top
|
|
|
trav
Joined: Sep 11, 2012 Posts: 108 Location: Auckland
Audio files: 16
|
Posted: Sun Oct 14, 2012 2:50 pm Post subject:
|
|
|
16 LFOs... I want to see your breadboard! |
|
Back to top
|
|
|
EATyourGuitar
Joined: Oct 28, 2010 Posts: 59 Location: Providence, RI
|
|
Back to top
|
|
|
trav
Joined: Sep 11, 2012 Posts: 108 Location: Auckland
Audio files: 16
|
Posted: Mon Oct 15, 2012 2:40 pm Post subject:
|
|
|
Ah, that makes more sense. I get the math; for some reason I thought you'd made the discovery in the course of some ambitious breadboarding and worked out the theory afterward. It's a great result! like waves crashing on a beach. Now I really do want to see a hardware implementation. |
|
Back to top
|
|
|
analog_backlash
Joined: Sep 04, 2012 Posts: 393 Location: Aldershot, UK
Audio files: 21
|
Posted: Wed Oct 17, 2012 4:56 am Post subject:
|
|
|
Just a word of caution
The VAZ modular software that you're using looked very interesting, so I searched for it and found the web site vaz-synths(dot)com. However, my Norton Antivirus flagged it up as an unsafe web site with 2 threats, so I didn't delve any further. It's a shame, because I would like to see more about it.
Gary |
|
Back to top
|
|
|
blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
|
Posted: Wed Oct 17, 2012 8:27 am Post subject:
|
|
|
The support forum for VAZ is http://www.kvraudio.com/forum/viewforum.php?f=147 so maybe have a look there? It probably is a false alarm ... _________________ Jan
also .. could someone please turn down the thermostat a bit.
|
|
Back to top
|
|
|
analog_backlash
Joined: Sep 04, 2012 Posts: 393 Location: Aldershot, UK
Audio files: 21
|
Posted: Wed Oct 17, 2012 3:36 pm Post subject:
|
|
|
Thanks for that link Jan. I notice that one of the topics listed on that site is about false positives for malware/viruses etc. from antivirus software, including Norton. This probably explains my problem.
Gary |
|
Back to top
|
|
|
|