Creating a Helium Voice App
They are a dime a dozen, and you may be surprised by just how simple it is to create a helium voice app, which can modulate the pitch of the user’s voice. This section creates a page that allows the user to record audio, which is saved to isolated storage, and to play back the sample with the option to change the pitch of the playback using a slider.
The code for this section is located in the Sensors/Microphone directory of the WPUnleashed.Examples project in the downloadable sample code.
MicrophoneViewModel class includes the following two commands:
ToggleRecordCommand—Starts the microphone recording if not recording; ...