Best with a steady 2 to 10 second loop, like an engine hum or a tone. It plays on repeat, gets higher as you speed up and louder when you accelerate.
Controls
Sound levelLoudness compared to your music
SensitivityHigher means full sound with a lighter foot
Play over my musicKeeps Apple Music playing underneath
Relearn phone directionUse after you move the phone mount
Parked test
Test modeIgnores the sensors so you can try sounds while parked
Setup (do this before you drive)
Connect your iPhone to the car with CarPlay or Bluetooth.
Start a song in Apple Music.
Turn off Silent Mode on your iPhone. Sounds that play over music are muted in Silent Mode.
Open this page in Safari and tap Start. Allow Motion & Orientation and Location.
Mount the phone so it can't slide or flip. Any angle works.
Leave this page open on screen while you drive. The screen stays on by itself, and the sound stops if you switch apps or lock the phone.
Drive normally for about a minute. The app learns which way the phone faces from your first few speed-ups and slow-downs. Until then it reacts a little slower.
Set the balance with Sound level here, and use the car's volume knob for everything together.
Optional: tap the Share button in Safari, then Add to Home Screen, so it opens full screen like an app.