Neutron Sound Orgone Accumulator

Complex triple Wavetable VCO

http://www.modulargrid.net/e/other-unknown-orgone-accumulator-

The idea of this is to be reasonably inexpensive and not use much more than a Teensy 3.1 and some op-amps and controls, so giant SD card waveform libraries and so on are out. there are quite a lot of controls though!

The sample rate is 80,000 hz, once this particular code is finalized, I may be able to increase it further.

the output is 12 bit, and the waves are 512 point 16 bit. there is an analog fixed 19khz 4 pole filter to keep too much digital HF from getting in your modules.

The 1v/octave input is real time converted, no look up tables or silly pitch bend schemes. the resolution is 1/72 of a semitone the range is over 8 octaves.

The idea is to have 3 waveforms which are interpolated between with the central knob and the "position" CV input. this way you can get a lot of variation with only one CV.

There are selectable waveforms on low, medium and high, the available waves change depending on what mode it is in (saw and square are not usually good for FM for instance so there are not many available)

At the most basic you can interpolate between them by turning the knob and fade perfectly smoothly between the different waves.
waves are selected to never cancel out and leave dead spots, as well as for their sound. (but not finalized yet) you could put in your own waves if you had the inclination.

the detuning is modulate-able, not only the frequency (which in normal mode can be an octave) but the amount via the detune enable buttons and the position. dynamic detuning is not something i have seen used much in synths, it is quite powerful.

In normal detune mode the detuned oscillators are evenly spaced above and below the main frequency, In prime mode, they are separated by prime numbers. this makes an overlap or "beat" of all the oscillators being in phase very unlikely to happen (i have not seen or heard it once yet) some other behaviour changes as well. in normal mode the range is much wider and you can do "hoover" octave up and down sounds.

I have called the modulation controls FREQ and INDEX, even though when not in FM mode that is not strictly true, but they do more or less the same thing. frequency and depth of modulation.

position, detune, index, and mod frequency all have analog attenuverter inputs, as well as the respective knobs

the main and fine tuning can be disabled to prevent accidental tweaks.
(it does not remember when turned off though)

http://neutron-sound.com/noa.html