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GTK · Bass

GTK – Bass Player's Toolkit

Tools for your bass journey.

The newest member of the family, built for the low end: chords, scales, arpeggios and fretboard knowledge for bass players. Coming soon to the App Store.

Coming soon to theApp Store See all tools
  • $9.99 one-time
  • Version 1.0.1
  • iPhone · iPad · Mac (Apple silicon)
G E C E
C major, open position, standard EADG

Highlights

Made for bass players

Chord Master

Browse chords by key, build them note by note, or place your fingers on the neck to name a chord – then hear it whole or arpeggiated.

Fretboard fluency

Learn every note on the neck with Note Practice drills.

Scales & positions

See scales and positions mapped to the bass fretboard.

Tuner & metronome

The essentials, built in and working offline.

Inside the app

See it in action

Chord Master on bass with the Library tab selected. Dm is typed in the search box, with a count of 22. Four-string chord diagrams for Dm, Dm/A, Dm/Ab, Dm/B, Dm/Bb and Dm/C are shown, each with a play button, a heart, an arpeggio button and, on some, a copy button.
Library: search for a chord and see how to play it on the bass neck.Chord Master guide
Chord Library on bass, the All tab with an empty search box and a count of 582 chords. Four-string chord diagrams for Ab, Ab/A, Ab/B, Ab/B♭, Ab/C and Ab/C♯ are shown in a grid, each with a play button, a heart and the note under each string.
The All tab: 582 chord diagrams, each ready to play.Chord Library guide
Edit Chord on bass: frets at base fret 2 on the A, D and G strings with the E string muted, named My Esus4, with its four-string chord diagram, the notes B, E and A, and play and arpeggio buttons.
Esus4 on the top three strings, with the E string muted, named and ready to save.Custom Chords guide
Chord Build on bass with the notes C, E and G switched on in red, green and blue. The name C is shown large, with Em3 and GP4 listed as alternatives at 67%. The fretboard shows every C, E and G across the four strings (G, D, A and E) from the open strings to fret 6.
Select C, E and G: GTK names the chord C and marks each of those notes on the neck.Chord Build guide
Chord Explore on bass with C, E and A♯ placed on the A, D and G strings at frets 3, 2 and 3; the E string is empty and shows dashes in the table. The name C7 is shown at 75% with ETT/C at 67% and A♯m9♭5/C at 60% as alternatives.
Tap the fretboard: three notes give C7, but only at 75%.Chord Explore guide
Chord Transposer with Actual Key C, Desired Key G and Capo on Fret 0. In the Chord Progression list, Instead of Cm, Dm, E7, E, G and Am becomes Play Gm, Am, B7, B, D and Em; the Capo column is empty and Effective matches Play.
C to G, no capo: Cm, Dm, E7, E, G, Am become Gm, Am, B7, B, D, Em.Chord Transposer guide
Scales on bass set to the C major scale: the notes C, D, E, F, G, A and B with scale degrees 1 to 7, and their positions on the four strings (G, D, A and E) as colour-coded note names.
C major across the neck, with its notes and scale degrees.Scales guide
Scale Sharing on bass with four scales listed: C Major (blue) and A Minor (green) switched on, F Major and G Major switched off. The fretboard shows each note in one of the two colours, with dots split into blue and green pie slices where the scales share a note.
C major and A minor: the same seven notes, so every dot is shared.Scale Sharing guide
Triad Sharing on bass, the Triads tab, with only C (blue) switched on and only the 123 string-set box ticked; 234 is unticked. The fretboard from fret 4 shows the notes C, E and G as blue dots on the top three strings only (G, D and A); the E string is empty.
One string set: with only 123 ticked, C’s triad appears on the G, D and A strings alone.Triad Sharing guide
Chord Sharing on bass, the Chords tab, with a box for entering a chord name and four chords listed: Daug9 (D, F♯, A♯, C, E), D7, Am7 and Emaj7. Only Daug9 (blue) is switched on. Its notes are shown across the fretboard (the four strings G, D, A and E), with the root D ringed.
Type a chord name, even an unusual one like Daug9: its notes across the neck, root ringed.Chord Sharing guide
Position Finder on bass set to the key of G major at fret 5: the notes G, A, B, C, D, E and F♯, with their positions on the fretboard from fret 3 to 10 and coloured rings marking groups of notes to improvise around. The shape is named A Dorian.
Song moves to G: its notes around fret 5, with rings to improvise in.Position Finder guide
Circle of Fifths with Key C and Mode Ionian. C is blue at the top of the wheel, F is red on its left and G is green on its right, with Am, Dm, Em and B° shaded inside. The centre of the wheel is empty because C has no sharps or flats. Below, Diatonic Chords in C Ionian lists I C, ii Dm, iii Em, IV F, V G, vi Am and vii° B° with the notes of each chord.
C Ionian: C major, with F and G either side and no sharps or flats.Circle of Fifths guide
Mode Converter turning C Dorian into D Phrygian, up 2 semitones, with the colour-coded notes and scale degrees of both modes.
C Dorian to D Phrygian: same notes, new home, up 2 semitones.Mode Converter guide
Note Practice on bass asking for the note A on string 1, with the answer shown at fret 2 on the G string.
String 1, note A: fret 2 on the G string.Note Practice guide
Triad Practice on bass showing C minor in 2nd inversion on the G, D and A strings at fret 8: the notes G, C and D♯ as coloured pills, with the ♭3 on the G string, the root on the D string and the 5th on the A string.
C minor, 2nd inversion, on the G, D and A strings at fret 8.Triad Practice guide
Tuner showing C♯ at 140.0 Hz, 17.1 cents sharp, on the needle gauge.
Needle gauge, cents offset and Hz readout.Tuner guide
Metronome at 120 BPM with four beats per measure, preset tempos, tap tempo and the current beat highlighted.
Set the tempo, tap it in, or pick a preset.Metronome guide

Everything included

Planned tools

Final feature list will be confirmed at launch.

Chords

Theory

Practice

Utilities

Tunings & fretboard

Fits your instrument

Chords
582 chords
Scales
80+ scales in 14 categories
Frets
20 · 21 · 22 · 24
  • 4-String StandardE A D G
  • 4-String Drop DD A D G
  • 4-String D StandardD G C F
  • 4-String E♭ StandardE♭ A♭ D♭ G♭
  • 4-String Drop CC G C F
  • 5-String StandardB E A D G
  • 5-String High CE A D G C
  • 5-String Drop AA E A D G
  • 6-String StandardB E A D G C
  • One-time purchaseNo subscriptions, no in-app purchases, no ads.
  • Works offlineEverything runs on your device. No account, no internet needed.
  • No data collectedAudio for the tuner is processed on-device and never recorded or sent.
  • Family SharingBuy once and share with up to six family members.
Coming soon to theApp Store Questions? Read the FAQ

The family

Play more than one?

v1.7.6

Guitar

Tools for your guitar journey

Chords
~3,600 chords
Tunings
8
Explore & Buy
v1.3.2

Ukulele

Tools for your ukulele journey

Chords
4,200+ voicings
Tunings
4
Explore & Buy
v1.3.3

Banjo

Tools for your banjo journey

Chords
10,000+ chord entries
Tunings
8
Explore & Buy