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Audio Settings

Configure how OnSpeed generates and delivers audio tones.

Volume Control

Hardware Volume Pot

If you installed a volume potentiometer (V4P: MCP3202 ADC Channel 1):

  • Volume Enabled: true
  • Low Analog: ADC value at minimum volume (default: 170)
  • High Analog: ADC value at maximum volume (default: 339)

The pot reading is linearly mapped between these values to produce 0–100% volume.

Default Volume

If you don't have a hardware volume pot:

  • Volume Enabled: false
  • Default Volume: Set to your preferred level (0–100%)

Mute Under IAS

The Mute Under IAS setting (default: 30 knots) silences all tones when indicated airspeed is below this threshold. This prevents nuisance tones during:

  • Taxi
  • Engine run-up
  • Sitting on the ground in wind

OnSpeed unmutes 5 kt above the configured threshold and re-mutes at the threshold itself — a small hysteresis band that keeps audio from chattering on touchdown when IAS oscillates a few knots around the cutoff.

Set Mute Under IAS to 0 to disable the cutoff entirely: audio is always on, useful for taxi-time tone checks or ground testing.

Stall warning still overrides in some conditions

When the audio is muted by the pilot (button press), the stall warning can still sound if AOA exceeds the stall threshold AND IAS is above the mute-under-IAS value. The IAS threshold prevents false stall warnings during ground operations.

3D Audio (Lateral G Panning)

When 3D Audio is enabled (true):

  • The audio tone pans left and right based on lateral G-force
  • In a right turn, the tone shifts toward the left ear (and vice versa)
  • In coordinated flight (ball centered), the tone stays centered
  • In a slip or skid, the tone shifts to one side

This provides subconscious coordination awareness — you'll notice the tone shift before you notice the slip/skid ball.

Requirements: Stereo audio wiring (both left and right channels connected). If you have mono wiring, disable 3D audio.

Vno Overspeed Chime

Plays a chime when IAS exceeds your aircraft's Vno (max structural cruising speed):

  • Vno Speed: Your aircraft's Vno in knots
  • Chime Enabled: true to enable
  • Chime Interval: Seconds between chimes (default: 3)

The chime repeats at the configured interval as long as you're above Vno.

G-Limit Warning

When Over-G Warning is enabled (true), a warning tone plays when the load factor exceeds the configured limits:

  • Positive G-Limit: Maximum positive G (default: 4.0)
  • Negative G-Limit: Maximum negative G (default: -2.0)

Audio Mute Button

The physical button on the controller (GPIO 12) provides:

  • Single press: Toggle audio mute on/off
  • When muted: Only the stall warning sounds (if conditions are met)
  • The status LED reflects the current audio state

Testing Audio

AUDIOTEST Console Command

Via USB serial (921600 baud), type AUDIOTEST to run an audio test sequence:

  • Plays the left and right speaker voice clips so each channel can be confirmed independently
  • Plays the ONSPEED solid low tone and the G-limit voice
  • Runs a continuous AOA range sweep that walks past every band edge — silent, low-pitch pulsing, ONSPEED solid, high-pitch pulsing, stall warning buzz — so every region of the tone map is heard back-to-back
  • Runs as a background task (doesn't block the console); reports "busy" if already running

If you hear no audio during the test, check:

  1. Audio wiring (see Audio Wiring)
  2. Audio panel is set to the correct input
  3. Audio panel volume is up
  4. Headset is plugged in