Microphone & Speaker You can output the sound through the microphone by selecting the speaker unit. This app has a speaker output switching function. Play the music and practice the song. You can listen to music and sing songs through YouTube. Try to use it as a loudspeaker or megaphone when you want to make a loud voice. If you can not hear your ears, try using this app as a hearing aid. Try heart sounds or heart rate sounds like a stethoscope with this app. Use your Bluetooth headset or Bluetooth speaker to output your sound. This app has a speaker output switching function. You can output sound through earphones or headset. Outputs the sound of the microphone through the selected speaker device. Sound from the microphone can also be played in the background. You can use karaoke microphones while playing music. You can use this app as your presentation microphone.