Orra Key User Manual

Orra Key is a free key detection plugin. Put it on a track or on the master, press play, and within a few seconds it names the key of what it hears: the key itself, its relative, the two codes DJ software uses for it, a MATCH percentage that says how sure it is, and the next most likely keys.

Then it puts the key to work. The chords of the key appear as tiles: click one to hear it, or drag it into your DAW and it lands as a MIDI clip named after the chord, at the session's tempo and time signature. Four borrowed chords from neighboring modes sit beside them for color. A transpose strip shows the key a sample would be in at every shift from −6 to +6 semitones, and MATCH TO lights the shift that puts it in your project's key. A clickable key wheel, a NOTES HEARD display and a tuning readout in cents complete the picture.

Orra Key never changes your audio. The track passes straight through with no latency, and the only sound the plugin ever adds is the short chord preview you hear when you click a tile.

This manual runs front to back. Getting Started covers the first two minutes, the Interface Tour names every part of the window, and Reading the Result explains what the numbers mean. Later chapters cover the key wheel, the chords, transposition, settings, and a few things worth knowing about how key detection behaves.

The window is a midnight-blue brushed-metal plate in four rows: the header, a row of three displays (the key card, the key wheel and NOTES HEARD), the chords card, and the transpose card. Hover over anything for a tooltip.

The key card, top to bottom.

How Orra Key listens

Orra Key measures the pitched content of the track, roughly 30 Hz to 2.5 kHz, with both stereo channels combined, and works out how much of each of the twelve notes it hears. It scores all 24 major and minor keys against that balance and names the best fit. The tuning offset is estimated from the same notes and taken into account first, so a detuned sample is not misread. Every second of tonal audio since the last fresh start counts the same, so the answer firms up the longer a loop plays. Chord previews are mixed in after the analysis has taken its copy, so clicking tiles never changes the key.

The key wheel lays out all 24 keys so that neighbors are musically close. It is the same numbering DJs use for harmonic mixing, and it is also a fast way to pick a key by hand.

Picking a key

Click any key on the wheel to use it. The key card says MANUAL KEY, the chords, the NOTES HEARD colors and the transpose strip follow your choice, and AUTO lights. Use this when you know better (the song is in A major and the loop leans minor), to work in the relative key, or with no audio at all, to explore the chords of any key. Clicking an ALSO LIKELY chip does the same.

The analysis keeps listening underneath: in place of MATCH the key card shows "Detected: ..." with what it still hears, and ALSO LIKELY is hidden. Click AUTO to go back to the detected key.

NOTES HEARD

Twelve bars, C to B. Each bar's height is relative to the loudest note, and the percentage above it is that note's share of everything heard. Gold bars are notes of the scale of the key in use (major, or natural minor for a minor key), and the rest are gray. The keyboard strip below marks the scale notes in gold, and the key's home note is printed in bold. Note names follow NOTATION.

NOTES HEARD always shows the audio as it plays, not the transposed view. A tall gray bar is worth a look: a borrowed chord, a bent blue note, or a sign that another key fits nearly as well (check ALSO LIKELY).

The chords card shows eleven tiles for the key in use: seven gold tiles IN THE KEY and four violet tiles of BORROWED COLOR. Its title names the key (CHORDS IN G MINOR), and adds the shift when the transpose strip has one selected (CHORDS IN A MINOR, SAMPLE +2).

Reading a tile

At the top, the Roman numeral: the chord's step in the key. Upper case is major, lower case is minor, ° is diminished, ø half-diminished, + augmented, and 7ths and 9ths add their number (V7, Imaj7). Below it, the chord name (Gm, Adim, Bb) and the notes it plays, low to high, spelled the way the chord is written: D7 reads D F# A C, never D Gb A C. The three short lines at the bottom are the drag grip. Hover a tile for its notes in the tooltip.

Click to hear, drag into your DAW

• Click and hold a tile to hear the chord on a soft electric-piano voice. It sustains while you hold and rings out when you let go. The tile glows with the sound and fades with it. Clicking another tile takes over at once.
• Drag a tile (hold and move a few pixels) and it becomes a MIDI clip: drop it on a track in your DAW.

In the key

The seven chords built by stacking thirds on each step of the key's scale. In a major key: I, ii, iii, IV, V, vi, vii°. In a minor key (natural minor): i, ii°, III, iv, v, VI, VII.

Borrowed color

Four chords from outside the key that producers reach for all the time. They come from a neighboring mode, so they sound like a change of light rather than a wrong note.

A borrowed chord keeps its own accidental: bVI in G major is Eb, not D#. With 7ths or 9ths, a borrowed chord is extended within the scale it comes from, so V7 in A minor is E7 (E G# B D).

The controls along the top of the chords card shape both what you hear and what you drag.

What lands in your DAW

• A standard MIDI file with one track. Every note of the chord starts at the top of the clip and is held for its full LENGTH, at velocity 100, with the voicing and register you chose.
• The clip carries the session's tempo and time signature: in a 3/4 session, 2 bars is two bars of 3/4. If the host reports no tempo, 120 BPM in 4/4 is used.
• The file is named after the chord (Am7.mid), so most DAWs name the new clip after the chord too.
• Drop it on an instrument track, or wherever your DAW accepts MIDI files. The files are written to a temporary folder that Orra Key tidies after ten minutes.

Building a progression

With VOICING on Smooth, drag I, V, vi and IV one after another onto the same track. Every chord takes the inversion closest to the middle of the register, so the voices move by small steps without any editing.

The transpose card answers two questions: what key will this sample be in if I pitch it, and how far do I pitch it to fit my song? Orra Key itself never pitches the audio. Use your DAW's or sampler's transpose control with the numbers shown here.

The transpose strip

Thirteen cells, from −6 to +6 semitones, with AS IS in the middle. Each cell shows the shift, the key the sample lands in, and that key's wheel code. Between them they cover all twelve keys of the sample's mode (−6 and +6 land on the same key).

Click a cell to see that key's chords: the chords card switches to it and its title says, for example, (SAMPLE +2), and the wheel outlines that key in white. Now pitch the sample by the same amount and drag chords that already fit it. Click the cell again to go back to AS IS.

MATCH TO

Choose your project's key in the MATCH TO menu (each entry shows its wheel code, for example Bb minor (3A); None turns it off). Then:

• The cell whose key is your project key, or its relative, fills gold: that is the shift that fits.
• Cells that land on a neighboring key (one step around the wheel from your project key, in the same ring) are outlined in gold, and those usually sit well too.
• The line beside TRANSPOSE spells it out, for example "Shift +2 (or -10) to sit in C major". Both moves reach the same key, one up and one down, and the smaller one usually keeps the sample closer to its original character. When no shift is needed it says "Already in ..." or "Already fits ..." (as its relative).
• A blue dot marks the MATCH TO key on the wheel.

Why the relative counts

A minor sample can sit in a major song, and the other way round, as long as the notes agree. An A minor loop fits a C major song as is: the same notes, the same chords. So Orra Key keeps the sample's own mode and aims for the project key's relative when the modes differ. A G minor loop in a C major song: Shift +2, to A minor, C major's relative.

NOTATION

Key signature (the default) spells notes the way the key signature writes them: Bb in F major, A# in B major. Key names follow the usual convention (Db major, F# major, C# minor, Bb minor), every chord tone takes its proper letter (D7 is D F# A C), and C major and A minor write their accidentals as flats, because their borrowed chords are on the flat side (Bb, Ab, Fm). Sharps and Flats spell every note one way, to match a piano roll or a habit. NOTATION applies everywhere: key names, chord tiles, NOTES HEARD, the wheel, the transpose strip and the MATCH TO menu.

UI scale

75 % to 200 % in steps of 25, from the menu next to the ? key. The size is saved with the session. If a saved size is too big for the screen it opens at, the window steps down until it fits.

Tooltips & languages

The round ? key turns the hover tooltips on and off (on by default). Right-click it for TOOLTIP LANGUAGE: English, Dutch, Japanese, Spanish, Brazilian Portuguese, German or French. Picking a language also turns the tooltips on. Control names such as LISTEN or TUNING stay in English in every language, so the tips match the panel.

Saved with your session

LISTEN, NOTATION, the chord options and TUNE, the PREVIEW level, a key picked on the wheel, the selected transpose cell, MATCH TO, the UI scale and the tooltip settings. The analysis itself is saved too: a reopened project shows its key, wheel and notes without playing a note. The first play after reopening starts a fresh listen, as after any stop of 2 seconds or more.

Keyboard & mouse