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4 Bit DPW Wavetable Editor & Player

AA LoFi Free Waveform Oscillator for Game & Chip Sounds

 (10 Votes)
2.0 (Updated 3 years ago)
720.9kB
July 03, 2021
Reaktor 6
Other Test Area

DESCRIPTION

There are some differences from just another "draw your own waveform" oscillator:

- The oscillator does not just read data from a table or/and interpolates this data. It generates a one sample DPW bandlimiting signal between every step to suppress aliasing. So it is a useful wavetable player even for high frequencies.

- For every waveform you draw, except flat lines, the oscillator calculates live a DC compensation. For flat lines you always get a zero. I leave the gap that at one resolution drawn waveforms may become flat lines at other resolutions.

- The oscillator is intended for game and chip sounds and has a maximum resolution of 4Bit (N * 1/16).


Since this oscillator needs one sample per step to suppress aliasing (and for other reasons) there is a frequency limit of SR/4*Resolution. (A new version with a better limit of SR/2*Resolution is in progress - solved with Version 2.0.) If this limit is exceeded the oscillator reduces the resolution automatically. Therefor you may use minimum 96 KHz SR.


Any proposals or criticisms are welcome.

Update Version 2.0:

- CPU optimized, very low load
- better UI
- display now shows also when resolution is automatically reduced
- display now shows also the audio output signal; so the DC compensation is visible
- added some things to play around to the test ensemble

COMMENTS  (4)

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andrew aronson
3 years ago
it actually sounded cool with your lofi oscillator, especially while drawing shapes with simultaneously with my free hand. it was only when i brought up the monark oscillator for a clean reference of what audio signal as pitch control for a block would sound like that i became aware of spending my time foolishly. i actually rectified the signal first for monark and it didn't seem to make much difference, what i can say is coming in with a hot signal is where most of the action is anyway, figuring out what about your DPW implementation is different than benjamen poddig's is been a rabbit hold i'd been intent on sorting out eventually, and though your previous offering seem like a more general case and therefore a better place to start, this talk about a one-sample square wave as DPW has stirred my interest enough to serve as an impulse to adventure. a single sample at a discontinuity, my first thought was "half a polyblep", though, my knowledge of antialising techniques is exclusively second hand folk wisdom
Frank Uhlmann
3 years ago
Hi, Andrew. I'm going to get my guitar out of the basement and see what we get. Since this block only takes positive pitch values, I fear bad things. I'll try to make it possible to feed the block with negative pitch values too. For DPW look into the audio core cell/phase+impulse/impulse; it's a 1st order square oscillator that only takes the one sample long up impulse to "connect" the table values.
andrew aronson
3 years ago
oh man, this loaded with the audio input hooked up to the pitch control, and for a good five minutes i was digging around inside, thinking to myself 'what the hell is this guy up to? think it gave me flashbacks of PLL month on the forum, but even with all that i had never once considered what would happen when using an audio signal as pitch control for a block. turns out.. i don't like it, i've heard enough PLL death screams now to last a lifetime i think, but it kinda did sound funky when my bass was plugged into it for a minute anyway, its nice to have a new antialiasing thing to study. i don't really see how it is DPW as i understand it, but i certainly take your word that it is
Thomas Alenfors
3 years ago
Love it! Thanks!
now