Overlay Features Tunings Pricing Get the App
Bass Theory App · Coming Soon

See what to play
over any chord.

The strong notes — root, 3rd, 5th, 7th — lit up right where your hand is. On your bass, in your tuning. Stop guessing the changes and start locking in.

The whole neck,
locked to the chord

E Minor 7 — overlay over E Dorian
Overlay Scales Arpeggio
R Root
3 3rd
5 5th
7 7th
Scale

Built for the
way bassists play

🎯

Chord-Tone Overlay

Pick a root and chord and the root, 3rd, 5th and 7th light up across the neck — color-coded so the notes that lock with the chord pop. The matching scale sits dimmed underneath.

🎸

4, 5 & 6-String

String count is built in. Standard, Drop D, low-B 5-string, 6-string and more — the whole fretboard recalculates for your bass and your tuning.

🎼

Scales & Arpeggios

The full scale and mode reference, plus a chord-tone arpeggio view — the bass staple — mapped across the neck and color-coded by interval.

📍

Position Lock

Pin the overlay to a 4-fret window and everything outside dims. See exactly what falls under your hand without losing the rest of the neck.

🔊

Real Bass Audio

Tap any note to hear it — recorded bass samples, pitched to the exact note, so it sounds like a real string fretted up and down the neck.

✏️

Custom Mode

Hand-pick any set of notes to highlight on the neck. Build your own shape, map a riff, or sketch an idea — your fretboard, your rules.

Your bass.
Your tuning.

Tuning isn't an afterthought — it's the foundation. Pick your instrument and string count, and every note on the neck follows. From a 4-string in standard to a low-B 5 or a wide 6.

4, 5 and 6-string necks
Standard, drop and down tunings
Every overlay, scale and arpeggio follows the tuning
4-String Standard
E A D G
4-string · Free
Drop D
D A D G
4-string · Free
5-String (Low B)
B E A D G
5-string · Pro
6-String
B E A D G C
6-string · Pro
Eb Standard
Eb Ab Db Gb
4-string · Pro
BEAD · Drop C · Drop A
+ more
low & extended · Pro

Faster than thinking

You're handed the changes. Three taps and you know exactly which notes lock with the chord — and where they sit under your hand.

01

Pick the chord

Set the root and chord quality. Triads, sixths and sevenths — the chords that actually show up on a chart.

02

Read the colors

Root, 3rd, 5th and 7th light up across the neck. The 3rd pops — it's the note that defines the chord. The parent scale sits dimmed underneath.

03

Lock your position

Pin a 4-fret window to your hand and the rest of the neck dims. Tap to hear it. Now you're playing the changes, not hunting for them.

Start free.
Own it forever when you're ready.

Free
$0
forever
  • Chord-tone overlay (triads)
  • Scale & arpeggio reference
  • Standard + Drop D tunings
  • Tap-to-hear bass audio
  • Position lock & scale underlay
  • Favorites & recents
Download Free
Monthly
$7.99
per month — cancel anytime
  • Everything in Free
  • All chords, incl. 7ths
  • All scales & modes
  • All tunings (4 / 5 / 6-string)
  • Custom mode
  • Built-in metronome
Subscribe Monthly

Coming soon to iOS and Android.