Capo is an especially useful tool for musicians wanting to play along with songs residing in their iTunes library. It lets you slow down (or speed up) the tempo of a song without having the pitch of the tune sound as if Alvin the Chipmunk or the Grim Reaper is on lead vocals. But pitch and tempo manipulation is just one of Capo’s handy features. The latest version of Capo for Mac adds automatic chord recognition, allowing you to start strumming almost instantly.
As soon as you launch Capo, a small square window with a musical note opens on screen, inviting you to drag and drop an audio file onto it. Capo supports MP3, M4A, AIFF, and WAV; it cannot open older DRM-protected files. Once you drop a supported file onto the window, Capo quickly processes the song and opens the main application view, which cleanly presents a vast amount of information about the tune.
Across the top of the window, you see a timeline with the song broken down into measures. Just beneath it is the waveform of the song’s audio. Beneath that, a spectrogram of the audio shows a lot more detail about the music, if you know what you’re looking at.
The spectrogram presents eight octaves’ worth of audio information that lets you see if the guitarist is using vibrato, bending, or sliding into notes, and more. The spectrogram can take some getting used to, however, as distortion and natural harmonics also show up there and can mislead you as you try to distinguish the intricate parts of the song.
The automatic chord recognition is not perfect, but it serves as a great, timesaving starting point. Capo analyzes each measure and marks the beginning of that measure with the chord that seems to dominate the measure. It also shows the chord’s fingering.
Songs that change chords in the middle of the measure can be tricky for Capo. For example, “Roadrunner,” by Jonathan Richman and the Modern Lovers, showed the correct A and D chords, but not in the correct position. If you encounter a song that the app doesn’t recognize to your satisfaction, don’t worry—it’s easy enough to fix. In my test, I simply slowed the song down to 3/4 speed and played the song through, tapping Command-K every time a chord change happened. Capo is much better at deciphering the chords playing at a precise moment in the music than at figuring out which single chord to mark down when more than one is being played in a measure.
The chords that Capo recognizes and writes out are not limited to guitar. Capo can write out the chords for ukulele, mandolin, and bass guitar, as well as for multiple alternate guitar tunings. Capo can even write out the chords based on whether the musician is using a capo on the guitar neck. Pretty amazing.
As with previous versions of Capo, you can select portions of the song to loop, which is very helpful when you’re learning complicated sections of the tune. You can also select, color-code, and label the sections as the chorus, verse, bridge, or whatever you’d like.
You can save the files that you work on either as a Capo file or as a MIDI file to play back in compatible applications. I wish I could save the chords or tablature out to file, to print or to use with other apps. The developers have heard such requests, and they’re continuing to work on that feature.
Capo makes learning new songs quick and fun. The app’s ability to write out the fingering of multiple instruments makes it easy to begin playing along to the songs in your iTunes library. Although the automatic chord detection isn’t flawless, it serves as a useful starting point.