Bandmate Chromatic Tuner

Try this if the Web version of Bandmate is not working for you:

Increase your microphone sensitivity.  Here is how to do this on a Chromebook: 
          At the bottom right corner of the screen, click on the time.
          Next to the volume slider, select Audio settings .
          Under “Input,” drag the microphone slider to the right.

Try this if the iOS version of Bandmate is not working for you:

Enable microphone permission.  Bandmate needs "permission" to use your device's microphone.  Here is how to do this:
            In the Settings app, tap Privacy. 
            Tap Microphone. 
            Find Bandmate Chromatic Tuner on the list of apps, and tap the switch so it turns green.