Although the iPhone has a built-in microphone, you may want to connect an external microphone to the device, particularly if you want to capture a high-quality signal. A number of third-party microphones are available for use with the iPhone. Connection methods vary. Some connect to the iPhone's headset jack, some to the Lightning port on iPhone 5 or later and others to the iPhone's dock connection port on iPhone 4 and earlier. Follow the microphone's documentation to connect it to the iPhone.
To launch the Voice Memos app, tap its icon on the iPhone's home screen. After the app opens, speak into the external microphone or the iPhone's internal microphone to get a signal level. The level meter is located at the bottom of the Voice Memos app. Practice singing into the microphone at the same volume at which you or the artist will be singing during the song. Move the microphone nearer or father from the singer so that the meter does not go into the red, which causes distortion on the recording. For best results, aim for a maximum level of around minus 3 to zero decibels on the meter. When you've achieved a suitable level, tap the "Record" button to record your track. Tap the "Pause" or "Stop" icons to pause or stop recording.
ImproVox is a voice-recording app with built-in harmonization and pitch correction functionality. After you download and install the app, tap its icon on the iPhone's home screen. Tap "Import" to import the song over which you want to record vocals, if applicable. After the song is imported, tap the "Record" icon to begin recording. The Record icon is red and has a picture of a microphone on it. When you are done, press the "Stop" button. Tap the "Controls" button to edit pitch correction and harmonization settings.
VoiceJam is a third-party audio-recording app for the iPhone that enables you to sing, loop and share vocal tracks. After you download and install VoiceJam, tap its app icon on the iPhone's home screen. Tap the "Record" button located in the center of the virtual microphone to begin recording and the "Stop" button when you are finished. For tutorials on more advanced functionality, tap the "Info" icon in the upper right corner of the main VoiceJam window. Tap "Tutorials" for in-app advice or tap "Demo Videos" to view instructional videos.
Because some audio-recording apps for the iPhone, including Voice Memos and VoiceJam, don't permit multi-track recording, you may need to employ a secondary device to enable the vocalist to listen to the song's base tracks while recording vocals. Provide the vocalist with headphones to prevent feedback during recording.
Information in this article applies to iPhones with iOS 6. It may vary slightly or significantly with other versions or products.