Find chords

The Chords page listens to the selected audio item and writes its chords onto a track named Chordtrack, the track Prest Server’s REAPER plugin shows chords from.

It needs the Chord recognition component. If the page shows Install, click it, or see Add the tools you need.

Find the chords

Map the tempo first if you want chords on bars: see Map the tempo.
Select the song’s audio item.
Open the Chords page and click Find chords.

Expected result, in one undo step:

The Chordtrack holds one empty item per chord, as long as the chord is held, with the chord’s name in the item’s notes. PresTools makes the track at the bottom of the track list if it isn’t there, and finds it by that name afterward: rename it, and the next run makes a new one.
The chords are spelled for the song’s key, followed through the song, so you get Fm/Eb in a flat key rather than E#m/D#. A key change is spelled in the new key, sometimes a few seconds early.
A silence inside the song is written N.C.. Silence before the song starts and after it ends is not.
The page shows how many chords it found and the song’s key.

Once there is a Chordtrack, the button reads Find chords again. It replaces only the chords under the selected item. Chords under other items stay, and so does anything on the track that isn’t a chord, such as an item you named “Bass comes in”.

What it hears

It writes triads, sevenths, 9ths, 11ths, and 13ths on dominants, sus and diminished chords, and chords over a bass note. It rarely writes a 6th, a b9, or a #9, even where the music has them: an A6 usually comes out as F#m/A, and a maj9 as maj7. It catches a passing chord of a beat or so at most tempos, but not the three or four chords a second of bebop. Correct what it missed in the chart.

Snap to grid

Tick Snap to grid before you click Find chords to put each chord on the project’s bars, to the nearest sixteenth. The Chordtrack then also shows as a chord chart you can edit.

Without a tempo map, the bars are REAPER’s default tempo, which has nothing to do with the song: map the tempo first. Leave Snap to grid off for a rubato performance; each chord then keeps the time it was heard at, and you edit the items on the track.

Edit the chord chart

With Snap to grid on, the page shows the Chordtrack as text, four bars to a line:

9: | C | G/B Am | F / G / | C . . . . . G7 . |

A line starts with its first bar’s number, such as 9:.
A bar is what is between two |. Its chords split it evenly: one fills the bar, two halve it, four are its beats. A 4/4 bar goes down to sixteenths.
/ or . holds the chord before. % repeats the bar before. N.C. is silence.
[Verse] on its own line starts a section at the next bar. Each section is a region in the project.

Chords are written as a chart writes them: C6, C6/9, Cadd9, C7b9, C7#9, CmM7, C13, Cmaj7#11, on any root and over any bass note, such as Am/F#. Common spellings are read too: Amin7, C-7, CΔ7, B°7, Fø, C69, and H7 for B7. A chord the recognizer has no part for, such as C7alt or C7b5, is marked as a mistake. Editing the chart needs the Chord recognition component too.

Edit the chart. Mistakes show under it, by line, such as Line 3: and what is wrong.
Click Apply chart to write it to the Chordtrack and the project’s regions, in one undo step.

Discard edits asks Discard your edits?, then goes back to what the Chordtrack holds. If the track changes while you edit, the page says The track changed while you were editing. Discard to see it.

Nothing else keeps a copy of the chart: the Chordtrack is the chart, and it travels with the project.

What it runs on

The GPU, unless you turn it off in Settings. If the GPU can’t run the recognizer, it finishes on the CPU. Hover over Find chords to see where it will run.

Next: Recognize and align lyrics.