The Shepard Tone Vario is pretty-much ready and will be released after some of my friends have tested it.

Version #1 was an attempt to create Shepard tones using the limited sound capabilities of the playTone() function of OpenTX Lua, but that didn't work out very well. The latest version uses a set of 100 WAV files that I spent many hours creating using a combination of several tools, including Audacity. This will almost certainly undergo further refinement but I believe it's quite functional in its current form.

Credit for the idea goes to Helmut Stettmaier, who describes it in the March 2018 issue of Radio Controlled Soaring Digest. Please read his article for more information.

Shepard Tone Vario Demo (5 min 54 sec)

Some Shepard tone videos:

The sound illusion that makes Dunkirk so intense (3 min 2 sec)

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Here's a simple improvement to the volume control setup I described in my previous blog post, which is a way to put your volume control on one of your potentiometers and confine its range to within your chosen upper and lower limits. The need to do arithmetic is now gone, plus there's a way to set the detent center position of the control to the "perfect" volume setting that's not too loud and not too soft.

If you haven't already guessed, the solution is to use a 3-point curve.

The first step is to create the curve. In this example I'm using Curve 32 and initially setting the three points to -100%, 0%, +100%:



The Special Function used is the same as in the previous setup:



But you can use a mix instead of an input if you like:

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