# About the Spectrogram

Capo provides a much more rich and powerful visualization of your music with the spectrogram.

Compared with the flat view of your audio provided by a waveform, the spectrogram shows you what frequencies are present in the song you're trying to learn, and how intense the energy is at any given frequency, at any point in time.

By viewing music with the spectrogram, you can deduce all kinds of information that is not at all possible in a waveform display. Here are some examples of spectrograms collected from a Stevie Ray Vaughan guitar performance, demonstrating various techniques that can be gleaned from the spectrogram.

## Vibrato

Vibrato is quite easy to detect, as it typically has a very obvious pattern to it. Capo's spectrogram doesn't just tell you that the bend is there—you are also able to deduce both the depth and rate of the vibrato using the spectrogram.

## Bends

A bend can sometimes look similar to vibrato if it's done quickly, but the telltale sign of a bend is that two distinct notes are often connected quite clearly. Compare to a vibrato, where the start and end note is not usually held for very long, and often over- or under-shot in pitch.

## Slides

A slide is usually easier to hear than to see, but I'm presenting an example for reference's sake. Note how slid notes have gaps in their path, and notes sitting cleanly in the semitone spacing. This corresponds to the individual frets being hit as the finger slides down the fretboard.

In contrast, a bend has a totally clear path from the origin to the destination pitch, because nothing is stopping the string from producing the notes in between the individual semitone pitches.

## Chords

When a chord is strummed on a guitar, you will often see notes being produced in a group such as the ones pictured below. Using the spectrogram to identify chords like this can help you identify a particular voicing of a chord you hear.

You should be careful, though, that you don't mistake harmonics for chords.

## Harmonics

Many instruments produce harmonics—multiples of the fundamental frequency—when they're played. As a simple example, if you were to play a C4 on an instrument, it could produce a harmonic that shows up at C5 when displayed as a spectrogram.

Harmonics can prove to be tricky, as they appear all over your music. Harmonics are part of the character of an instrument, and different instruments have varying levels, and spacing, of harmonics—they can even appear at lower frequencies from the fundamental! To make matters even more confusing, sometimes the fundamental won't appear at all!

Notice the example below we see a repeated bend from C#6 to D#6. Harmonics appear 7 semitones up, and 12 semitones up in that image. That is, a perfect 5th, and an octave, above the fundamental note that's being played. The rich harmonic character of the note is characteristic of a guitar playing a single note with distortion.

If you listened to the passage, though, you would hear that it is actually a C#5/D#5 bend. In this case, you would mark entries for a C#5/D#5 bend, despite not seeing any clear indication of the notes there. Harmonics can cause a lot of confusion if you're not aware of them to begin with!