Helmut Stettmaier in Bavaria, Germany, originally described the Shepard Tone Vario concept in the March 2018 issue of the now-defunct Radio Controlled Soaring Digest. It's the first article in that issue and the title is "An Innovative Method for Acoustically Rendering Climb Data for Model Gliders Using Shepard Tones."

The idea is that when your glider is circling in and out of lift and alternating between rising and falling, all you'll hear from a conventional variometer are high-pitched beeps while you're rising and lower tones while you're descending. The problem is that it won't tell you whether you're achieving a net profit or loss in altitude with each circle. Helmut offered a solution for that, which I call the Shepard Tone Vario.

The Shepard Tone vario isn't technically a variometer because it doesn't directly indicate vertical speed. Instead it produces a tone with a pitch that varies directly with altitude. It's a sort of audible altimeter that produces rising and falling tones instead of numbers. If you're circling in and out of lift you'll hear the tone rise and fall as you go around and your glider rises and falls, and you'll be able to hear whether the highest pitch you reach during a circle is higher, lower, or the same as the highest pitch you reached during the previous circle.

But the magic is in the Shepard tones. Shepard tones are auditory illusions. They can seem to continuously rise or fall yet never go beyond your range of hearing....Continue Reading

Looking back at the 2019 MidSouth ALES and F5J competitions and comparing them to the same contests at the 2019 Soaring NATS, it occurred to me that there was an unexpected benefit in the way it was done at the MidSouth, which was to interleave rounds in the two events and allow participation in one or the other but not both. At the Soaring NATS, ALES was held on Saturday and Sunday while F5J was held on the following Monday and Tuesday, allowing fliers to enter both contests.

At the MidSouth there were 17 in ALES and 15 in F5J, which was almost an even split. As I see it, the serious competitors who prefer strict rules, practice hard and often, and strive to master complex strategies, were separated from the less serious who were there mostly to enjoy soaring and socializing with those who share their hobby. In other words, the MidSouth one-contest-or-the-other structure separated the FAI crowd from the AMA crowd and, I suspect, made the event more appealing and enjoyable for everyone.

I'd like to see this format catch on, at least in major events, and perhaps it could even be extended to Thermal Duration vs. F3J.