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How to Make a Single-Cycle Waveform

chysn

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How to Make a Single-Cycle Waveform
« on: September 27, 2015, 04:52:01 AM »
If you want to create single-cycle waveforms for your Evolver, but don't know how to do it, this is where to find help!

You'll need audio editing software. Discussion of the best audio editing software is beyond the scope of this post, but it may be discussed later in the thread. For now, I'll give two recommendations. For PC, Mac, and Linux systems, Audacity is a very robust, and free, waveform editor. You may download it at http://audacity.sourceforge.net/download/.

For iOS devices, I would recommend TwistedWave. This is very full-featured. When I bought it, it was in the ten-US-dollar range, but it's very nice.

First, record your full waveform, or open an audio file. Once you have the file created, it'll look something like this:



If your original waveform is in stereo, you'll want to convert it into mono. To do this, click on the caret in the upper-left corner of the waveform window and select "Split Stereo to Mono."



Once you have them split, go ahead and close one of the two waveforms.

This waveform is much too big to be used in an Evolver. You want to grab a single "cycle" of that waveform. To find a cycle, you need to zoom in. For the Mac, you press Command-1 to zoom in. To find the key binding on your platform, open the View menu at the top of the screen. Try it... zoom into the waveform a few times:



As the waveform gets longer on the screen, you'll need to use the scrollbar at the bottom of the screen. (You can also resize vertically at the bottom of the waveform window.) Keep zooming until you can make out a single distinct data points:




Now you can extract a single cycle of this waveform. Find a point where the wave is at the center line and ascending. Then, find the next point where the wave is as close as possible to the center line and ascending. Click on the first point, and drag to the second. The point you choose may be arbitrary, or you may experiment with different points. In my wave, I've chosen a range more or less at random:



Now, at the top of the screen, go to Edit > Remove Audio > Trim. On a Mac, this is Command-T. Only your selected single-cycle portion will remain.

Export your file with File > Export. Audacity gives you a lot of options for saving the waveform in different formats. But the default format should be "WAV (Microsoft) signed 16 bit PCM." Evolver waveforms are transferred as 16 bit signed PCM.

Now the wave is prepared to be converted to the Evolver system exclusive format for sending to your Evolver. You may bring your WAV files into a utility like WAV2Evolver http://wav2evolver.dsi-lifeboat.com for conversion to system exclusive. Information on this process is in another thread on this forum: http://forum.davesmithinstruments.com/index.php/topic,38.0.html

Questions or comments? Talk below!
« Last Edit: October 10, 2017, 07:41:19 PM by chysn »
DSI: DSM03; previously: Mopho Keyboard, Desktop Mopho, Evolver, DSM01
Hardware: Eurorack, Moog Little Phatty w/ CV Outs, Arturia MicroBrute, KMI QuNexus
Software: macOS, Ableton, MuseScore
Modular Grid: https://www.modulargrid.net/e/racks/view/354385
GitHub: https://github.com/chysn

Re: How to Make a Single-Cycle Waveform
« Reply #1 on: October 10, 2017, 01:10:27 PM »
...Once you have the file created, it'll look something like this:



Questions or comments? Talk below!

What happened to the pics?

And... why create your own waveforms?  Demos of how to use this to do something substantially different than what's included?  (Don't mean to be devil's advocate, just don't really know how to benefit from the process)

chysn

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Re: How to Make a Single-Cycle Waveform
« Reply #2 on: October 10, 2017, 07:43:56 PM »
What happened to the pics?

I let that domain expire. I updated the URLs to the alternate domain. Thank you for pointing it out.


Quote
And... why create your own waveforms?  Demos of how to use this to do something substantially different than what's included?  (Don't mean to be devil's advocate, just don't really know how to benefit from the process)

The specific context here is creating single-cycle waveforms for the purpose of transferring them to an Evolver as custom waves. There might be other reasons to do it, but that's why this tutorial is here.
DSI: DSM03; previously: Mopho Keyboard, Desktop Mopho, Evolver, DSM01
Hardware: Eurorack, Moog Little Phatty w/ CV Outs, Arturia MicroBrute, KMI QuNexus
Software: macOS, Ableton, MuseScore
Modular Grid: https://www.modulargrid.net/e/racks/view/354385
GitHub: https://github.com/chysn