Google's Sound Amplifier takes sound picked up by your phone's microphones and pipes it directly into your earbuds. It's a great idea, but its utility has historically been limited by the app only working with wired headsets. Version 3.0, rolling out now, lifts that restriction, finally letting users listen through Bluetooth headphones.
The ability to listen wirelessly greatly enhances the app's usefulness; if you're trying to hear something more than a few feet away (Google gives the example of a lecturer), you can now place your phone near the sound source and move about freely — within Bluetooth range, anyway.
On Pixel phones, the app can also now amplify on-device sound. It doesn't actually make your headphones any louder, but it does tweak audio balance in such a way that voices should be easier to pick out.
Google's been on a streak of accessibility improvements this week: Google Maps was updated to highlight wheelchair-accessible places, and a new app called Action Blocks lets you create custom widgets to more easily access Google Assistant routines.
Sound Amplifier 3.0 is rolling out through the Play Store now. You can also grab if from APK Mirror.