These days, guitarists who want to learn a song often head straight to the keyboard—the computer keyboard, that is—to look up lyrics, chords, tab, a performance video, lesson, or music-learning software. The newest version of a Mac application called Capo, released last fall, promises to take computer-aided learning of songs to a new level—and even detects chords and generates tab. Eager to see how the app works, I got Capo 3 up and running on my MacBook Pro.
Getting started is easy: pick a song from your iTunes library (any unprotected mp3, m4u, aiff, or wav file), and Capo 3 quickly delivers a graph of the song’s harmonic content called the spectrogram, placed over a tempo grid, plus a sequence of chord grids and an empty tab system across the bottom. Then comes the fun part.
Got a song that flies by too fast for your brain and fingers? A slider allows you to slow the song down to 25 percent of the original tempo (or, if you are a masochist, speed it up to 150 percent) without affecting the pitch. Want to transpose? Using the same slider, you can raise the pitch up to two octaves (for the Alvin and Chipmunks effect) or lower it two octaves—and the chords automatically reflect whatever key you choose.
Pitch adjustment comes in handy if you want to play a song in a different key, or if the guitar on the track is tuned, say, down a half step and you want to bring it up to standard tuning. The quality of speed- and pitch-adjusted audio is quite good, and you can export it if you’d like to have, for example, a slowed-down version of a song on your iPod to practice with.
If you want to zero in on a passage, Capo 3 makes it easy to loop a region, and it provides useful tools for hearing the guitar part more clearly. You can pan the audio (in case the guitar is primarily on one side of the stereo mix), use EQ, or try voice reduction (with built-in settings for male and female voices).
The real groundbreaking feature of Capo 3 is chord detection. I tested it with a bunch of songs—including the Beatles’ “And I Love Her” and the Milk Carton Kids’ “Honey, Honey”—and found that Capo 3 gives you a good start, but gets some chords wrong and misses changes, too. So you need to use your ears and clean up the chords, which is straightforward: click a chord and hit delete to remove it; double-click to select a different fingering of the same chord, or an entirely different chord, from an extensive library of chord grids (a chord sounds when you click it, so you can judge by ear if you’ve got the right one). While the song is playing, you can also press ‘k’ when you hear a chord change, and Capo 3 detects a chord in that spot. (Note that at press time, an update of Capo was coming soon with a new chord detection engine the developer says is much more accurate—so the next iteration of the app may require less correcting of the chords.)
My favorite features of Capo 3 are the drop-down menus on which you can change the tuning and the capo position—and then the chords (and tab) automatically adjust. Choose from 55 tunings, including the most common as well as esoteric options like “double drop Bb” and “Guinnevere” (David Crosby’s EBDGAD). The tuning notes aren’t listed, so Googling may be required to know what some of the programmed tunings even are. You can also choose a capo position all the way up to the 18th fret—no partial capos, though. Another menu allows you to change the instrument: switch the chords to uke (in your choice of five tunings), mandolin, five-string banjo, or bass.
Generating tab on Capo 3 is a somewhat tricky process that’s most applicable to transcribing single-note solos. You look at the spectrogram—fuzzy gray shapes representing all the pitches detected—and click around to find the target shape or pitch. Draw the note with the mouse over the spectrogram and Capo 3 automatically places it on the tab. It’s easy then to move your note up, down, earlier, or later by clicking and dragging. But you can’t edit the tab directly—you have to make changes on the spectrogram. Because the same notes can be played in multiple places on the fingerboard, you can select a single note (or a group of notes) to move it to a different string in the tab.
Given the relative complexity of the tabbing process, I suspect that many guitarists will use Capo 3 primarily for its speed, pitch, tuning, and capo functions. Another missing feature, is the ability to export or print a chord chart or tab sheet (though you can export notes you entered as a MIDI file). Clearly, this is an app for learning songs, not for creating charts.
Though guitarists may fantasize about an app that can generate an instant, perfect transcription of a song, such a thing may never exist given the complexities of music. What Capo 3 does is give you some remarkably powerful tools for analyzing a song and mapping it out in different ways on the guitar. I actually like that the app requires you to use your ears—the process of correcting chords and drawing notes is great ear training and has benefits beyond the specific song you’re trying to learn. This smart, sophisticated app is well worth a look for any players who want to translate more songs from their Macs to their fingers.
Mac OS 10.9/Mavericks. (An iPhone/iPad version is available but lacks key features of Capo 3. An update is in the works.)
SuperMegaUltraGroovy.com. Free demo available.
Jeffrey Pepper Rodgers (jeffreypepperrodgers.com),Acoustic Guitar’s editor at large, is author of Songwriting Basics for Guitarists (Stringletter) and the Homespun video seriesLearn Seven Grateful Dead Classics for Acoustic Guitar.