Vocal Lab AU
is an Audio Units plug-in version of Vocal Lab which helps you train to sing on key. It listens while you sing and displays the pitch of your voice on a graph, in real time. All you have to do is watch the graph while you sing and try to stay near the lines. With a little practice you can greatly improve your intonation.
Vocal Lab AU can identify problem areas in your singing, and can also help improve your intonation on various instruments - Violin, Brass, Woodwinds, and more.
Requires an application that supports "Cocoa" Audio Units plug-ins such as GarageBand '08 and later, Logic Pro 7.1 and later, Logic Express 7.1 and later.