To maintain aircraft control, the pilot has to manage alpha (AOA), beta (sideslip or yaw angle) and energy. Our tone logic already allows the pilot to listen to AOA and an optimum turn/glide condition; so our latest experiment is to add sideslip cues to the mix. We think our yaw logic is about as caveman simple to use as our AOA/pitch logic which may help folks avoid an inadvertent loss-of-control.
The way we do this is by "slewing" the tone left or right in the sound field to match the position of the slip/skid ball in the slip/skid indicator...if the ball slides right, the tone slides right. If the ball goes left, the tone goes left with it. It turns out the human brain is remarkably good as perceiving the direction a sound comes from. To make this work, we use the basic stereo capability of the intercom system or stereo headset in the airplane. If the airplane has a stereo ICS, the V3 box outputs a stereo signal that is transmitted directly to the pilot (if he is wearing a stereo headset). If the intercom is mono, but the pilot's headset is stereo and has bluetooth, then the V3 can transmit directly to the headset. You "step on the tone" the same way you "step on the ball" to coordinate the airplane--you just don't have to look in the cockpit to do it. Like the AOA tone, it's a bit like flying with an instructor that reminds you to make a correction!
Since a picture is worth a thousand words, here's a short video of the system in action:
The gain for the logic is pilot adjustable, so you can select how pronounced you'd like the audio shift in direction to be. We have a central "neutral" band just like we do with the ONSPEED cue to provide damping and improve usability of the logic.