You want to learn to play your new favorite song, so you start looking for guitar tabs for it on the internet. Those tabs are only as good as the person who created them, though. If you want to be sure you get the correct tabs, you need the Capo 3 app for Mac. The app uses the audio-to-note approach to “listen” to any music file you have in your iTunes library. It slows the music down, analyzes the sound to detect chords, and quickly creates guitar tabulature. You can see a spectrogram, a visual representation of the frequencies of sound, of the song, so you can “see every nuance in the performance – the note bends, slides, and vibrato” to help you learn more about how it should be played. Capo 3 is $29.99 in the Mac app store.