I may be weird, but I see four scenarios in which an audio AoA meter would be helpful enough to me that I'm tempted to prototype one:

1. Aerotow, increasingly raucous warning as AoA approaches stall. Recognized by landing gear down, acceleration profile corresponding to aerotow, dynamic pressure has been close to zero since last time landing gear was up.

2. Winch launch, gentle progressive audio warning if AoA goes above or below optimal (calibrated best L/D AoA?), increasingly raucous warning as AoA approaches stall. Recognized by landing gear down, acceleration profile corresponding to winch launch, dynamic pressure has been zero since last time landing gear was up.

3. Thermaling, gentle progressive audio warning if AoA goes above or below optimal (calibrated minimum sink AoA?), option to provide stall AoA warning if it's not annoying. Recognized by landing gear up, appropriate dynamic pressure, acceleration magnitude greater than 1G for 10 seconds or so.

4. Approach, gentle audio warning if AoA goes above or below calibrated approach AoA, increasingly raucous warning warning as AoA approaches stall. Recognized by landing gear down (combined with gear warning if dive brakes open), dynamic pressure has not approached zero since last time landing gear was up.

AoA measurement filtered by a few seconds of moving average combined with gust filtering. If it's quiet, I'm almost certainly doing OK, only annoying if I get out of the envelope for a given scenario. Fairly trivial to program using a pair of available cheap high resolution digital interface differential pressure sensors and a two port probe. Recognizing the difference between aero and winch launch will likely take a bit of cleverness.