If you’re a guitarist, Capo is the bionic upgrade you wish you could give your ears. Drag any track from your iTunes library into Capo, and it quickly displays the music as visual data--a spectrogram full of blue smears. Those smears represent notes in the recording; the smears near the top are the higher-pitched notes and the ones below are the lower pitches. Click the cursor on a spectro-smear to hear its corresponding MIDI note. If that note is part of the solo or chord you are trying to figure out, drag the cursor on it a bit and, like magic, a tablature number appears below, showing you exactly where to place your fingers on your guitar.