KeyJ User Manual
Version 1.1 · iOS, Android, macOS · JoyPunk LLC
1. Overview
KeyJ is a music theory reference app for musicians, DJs, and producers. It combines the Circle of Fifths and the Camelot Wheel in a single interactive interface, letting you explore any key's signature, scale degrees, diatonic chords, and compatible neighboring keys in seconds.
KeyJ is free to download. A yearly subscription unlocks advanced features. A 10-day free trial is available from the premium screen so you can try everything before subscribing.
3. Key Explorer
The Carousel
The carousel displays all 12 keys as cards arranged in a horizontal wheel. Swipe left or right to move through the keys. The currently selected key is centered and shown in the highlighted color. Cards to the left and right show the adjacent keys.
Each card shows:
- The key name
- The Camelot number and slot (A for minor, B for major), when the Camelot Wheel view is selected
- Scale degree badges marking the tonic (I), subdominant (IV), and dominant (V) positions
The Banner
The banner above the carousel shows the active wheel type: Circle of Fifths or Camelot Wheel. The arrows on the left and right indicate the direction of flat and sharp keys as you swipe: swiping toward the flat arrow moves to keys with more flats; swiping toward the sharp arrow moves to keys with more sharps.
Header Cards
Below the carousel, a row of header cards shows the current key's most-used attributes at a glance:
| Card | Shows |
|---|---|
| Key | The selected key name and type (Major / minor) (shown in Camelot Wheel mode) |
| Key Signature | Number of sharps or flats |
| Relative Key | The relative major or minor key |
| Camelot Key | Camelot number and slot (shown in Major/minor mode) |
Long pressing a header card toggles the related setting without opening the settings screen. For example, long pressing the Key card toggles between Major and minor; long pressing the Camelot Key card switches between the Circle of Fifths and the Camelot Wheel.
Wheel Type
Switch between two organizational views in Settings or by long pressing the Camelot Key header card:
- Circle of Fifths: keys arranged by ascending perfect fifths, grouping relative major and minor pairs.
- Camelot Wheel: the same relationships mapped onto a numbered clock face (1-12) with A (minor) and B (major) slots, the standard reference used for harmonic mixing.
Key Type
Toggle the carousel between Major and minor keys. The carousel always shows 12 keys; switching key type reloads it with the corresponding set. Long press the Key header card to toggle without opening Settings.
Accidental Style
Choose whether keys with two possible spellings are displayed as sharps (C#) or flats (D♭). Change this in Settings or use the quick-settings panel from a long press on the main screen.
4. Detail Table
Below the header cards, the detail table lists all seven scale degrees for the selected key and mode. Each row shows:
| Column | Description |
|---|---|
| RNA | Roman Numeral Analysis label (I, ii, iii, IV, V, vi, vii° for major; i, ii°, III, iv, v, VI, VII for minor). Uppercase = major chord; lowercase = minor chord; ° = diminished. |
| Nashville Number (NSH) | The same degrees as Arabic numerals (1-7), the shorthand used in Nashville session playing. |
| Note | The scale note at that degree. |
| Chord | The diatonic chord built on that degree. Pentatonic and Blues scales suppress chord columns because those scales do not define a full diatonic set. |
Numbering Style
The detail table can display degree labels as RNA (Roman numerals) or Nashville Numbers. Change this in Settings under the Music section.
5. Scale and Mode Selector
A scale/mode button appears below the header cards when you are in Key Explorer or Instrument Mode. Tap a button to apply that scale or mode. The detail table and instrument display update immediately.
Free scales
- Major / Ionian
- Natural Minor / Aeolian
- Dorian
- Pentatonic
- Blues
Premium scales Premium
- Phrygian
- Lydian
- Mixolydian
- Locrian
- Harmonic Minor
- Melodic Minor
6. Instrument Mode
Instrument Mode shows the currently selected key mapped onto a physical instrument layout. Access it from the universal menu under Instrument View.
Three instrument layouts are available:
- Piano: a piano keyboard with the scale notes highlighted.
- Guitar: a six-string guitar fretboard with scale positions marked.
- Bass: a four-string bass fretboard.
The scale/mode selector is visible in this view. Changing the key on the carousel, switching modes, or toggling major/minor all update the instrument display in real time.
7. Semitone Converter
The Semitone Converter transposes a starting key by a given number of semitones. Access it from the universal menu under Semitone Calc.
How to use it
- Navigate to the key you want to start from using the carousel.
- Tap Set Key 1 to lock the current key as Key 1.
- Spin the carousel to set Key 2, or continue to step 4.
- The display shows the interval in semitones between Key 1 and Key 2, along with the enharmonic equivalent of Key 2.
Use this to quickly check capo positions, transposition intervals, or enharmonic equivalents without doing mental arithmetic.
8. Live Session
Live Session lets one device broadcast the current key to any number of connected followers in real time. When the leader changes keys, every follower's screen updates immediately.
Open Live Session from the universal menu under Live Session.
Leading a Session Premium
- Tap Lead a Session.
- A 4-character session code is generated. Share this code with your session mates by reading it aloud, copying it with the tap-to-copy shortcut, or using the share sheet.
- Return to the Key Explorer. Your current key is now broadcasting to all followers.
- Change keys on the carousel as normal; followers see each change in real time.
- To end the session, return to the Live Session screen and tap End Session.
While leading, a session badge is displayed at the top of the main screen showing your role and the session code.
Following a Session
- Tap Follow a Session.
- Enter the 4-character code from your session leader and tap Join Session.
- The carousel snaps to the leader's current key. When the leader changes keys, your view updates automatically.
- While following, the carousel is locked; you cannot manually change keys.
- To leave, return to the Live Session screen and tap Leave Session.
Following a session is free. Leading a session requires premium.
Prevent Screen Lock Premium
The Live Session screen includes a Prevent Screen Lock switch. When enabled, the device display stays on for the duration of the session. This setting is not saved between sessions. Prevent Screen Lock can also be configured persistently in Settings.
9. Settings
Open Settings from the universal menu. Settings are grouped into sections.
Appearance
| Setting | Options |
|---|---|
| Theme | Light, Dark, Midnight (free) Classical, Cute, Disco Premium |
| Accidental Style | Sharp, Flat |
Music
| Setting | Options |
|---|---|
| Key Type | Major, Minor |
| Numbering Style | RNA (Roman Numeral Analysis), Nashville Number |
| Wheel Type | Circle of Fifths, Camelot Wheel |
| Scale/Mode Type | See Scale and Mode Selector |
Live Session
| Setting | Description |
|---|---|
| Prevent Screen Lock Premium | Keep the display awake while the app is in use. Useful during performances and teaching sessions. |
Support
Links to rate the app, reset all settings to their defaults, and contact JoyPunk support.