Waveform/wavetable oscillators

Wow, it's been a while since I've posted anything. But christmas is here, I'm back at my in-laws and the creative juices are flowing once again ;)

This morning I started out searching for drum machine roms - more specifically for the Linn drum machines, but extended to the DMX/DX, Sequential Circuits Drumtraks and finally the sample roms for the 909.

I found most at http://www.electrongate.com/dmxfiles/index.html - and the Linn drum ones can be found using the wayback machine and searching for electrongate, they have been removed from the Electrongate site for copyright reasons. The 909 roms can be found as 8-bit wav files at http://www.colinfraser.com/tr909/my909.htm (they are shifted by two bits to get 8 bits, the two lowest bits are not used). The original 6 bit hex files can be found at https://nuxx.net/wiki/9090

But having found these, I started wondering if I could find more famous and useful roms. I remembered searching for the PPG Wave waveforms many years ago. I can't remember if I actually found them, but this time around it was near impossible. I did find some stuff but it's for the Waveterm and probably not the original waves.

I did however realise that it is hard to search for something without knowing the proper terms. After a while I found a post where someone were looking for the same thing, so here are some useful terms:

- Waveform

By definition "a curve showing the shape of a wave at a given time."

- Single cycle waveforms

This is as the name suggests, one cycle of a (complex) waveform. For a sine wave it would be one top and one bottom. By searching for this I found Adventurekid (https://www.adventurekid.se/akrt/waveforms/) which has a ton of waveforms.

- Wavetable

Now, this is where it gets confusing. There are various definitions, but a good one seems to be:
A table of (single cycle) waveforms. Often, these are varied over a wavetable, and moving/interpolating between them changes the timbre of a tone.

- Table-lookup

As in 'table-lookup oscillator', using part of a wavetable as the source of an oscillator

See here for a full explanation: https://en.wikipedia.org/wiki/Wavetable_synthesis

Here is a threat about interpolation on the PPG Wave and its successors: https://www.gearslutz.com/board/electronic-music-instruments-and-electronic-music-production/1273412-ppg-wave-doest-interpolate-between-single-cycles.html

A great resource for all things PPG: http://www.ppg.synth.net/waveterm/wt_lib.shtml

...and the waveterm: https://www.hermannseib.com/waveterm/history.shtml

http://synth.stromeko.net/Downloads.html

and about finding the single cycle wavs: https://www.kvraudio.com/forum/viewtopic.php?t=256143

More about the waveforms: https://www.kvraudio.com/forum/viewtopic.php?t=135120


For a nice article, check this out: http://www.muzines.co.uk/articles/a-deeper-wave/1042