Centerline

Available now on Android

Whole-guitar tuning guide

Half-step-down tuner guide for guitar

Half-step down lowers every string one semitone: E flat, A flat, D flat, G flat, B flat, E flat. That changes the feel of the entire instrument, so the safest routine is to retune all six strings in order and then make one short cleanup pass after the neck settles. Centerline can do that in the public Android release today, provided you work one string at a time and avoid ringing the whole chord while the app is listening.

Get it onGoogle Play

Free standard tuningUS $3.99 one-time unlock

How to tune it

Move the whole guitar together instead of chasing one string.

Half-step-down tuning is common when you want a looser feel, easier vocal keys, or a familiar fretboard with slightly lower pitch. Because every string changes, the neck tension also changes. Tune the low E to E flat first, continue through A flat, D flat, G flat, B flat, and the top E flat, then come back for a second pass. That second pass is usually short, but it matters more than in Drop D because the bridge and neck have moved as a group.

Centerline's public app is still aimed at guitar targets rather than an open-ended chromatic workflow, so it is happiest when you deliberately pick each string and let the reading settle. Guitar view is a good first pass because you can see where you are on the instrument, while Strobe helps on the cleanup pass once the strings are already near the note.

Centerline workflow

  1. Unlock alternate tunings once if half-step down is still locked in the app.
  2. Select the half-step-down preset and pluck each string cleanly from lowest to highest.
  3. Use Guitar to identify the string and get close to E flat, A flat, D flat, G flat, B flat, and E flat.
  4. Wait a few seconds, then run a second pass because the lower total tension can shift the earlier strings.
  5. Switch to Strobe only for the final tiny corrections if you want a slower visual settle.

What the public app can do today

  • The Android release includes four displays: Simple, Guitar, Strobe, and All strings.
  • Half-step-down tuning is included in the one-time unlock. Standard tuning remains free.
  • It is a strong fit when you want a ready-made semitone-down target and a clean pass across the full neck.

The biggest mistake here is strumming several strings at once. The public auto-detect flow is faster when the app hears one note clearly and does not have to guess which Eb or Bb you intended.

Why players use it

Same shapes, lower tension, easier keys.

Half-step-down guitar keeps the normal fretboard relationships while moving the entire instrument down. Singers often prefer it because familiar chord shapes land slightly lower without a capo, and electric players like the softer string feel. It is also a practical way to match a bandmate who is already tuned down by one semitone.

Centerline fits that use case because it opens quickly, stays offline, and keeps the screen readable from a stand. If you already know you want Eb tuning, the current Android build is enough: no ads, no account, no background networking, and a one-time unlock instead of a recurring fee.

Related guides

More Centerline tuning references

Drop D tunerLower only the sixth string and cross-check it against the open fourth string. DADGAD tunerRepeated Ds and As need a cleaner one-string-at-a-time pass. Open G tunerAnother full retune with lower tension across the neck. A4 calibrationKnow when 440 Hz is right and when another instrument calls for a different center. Strobe vs needlePick the right display for first-pass moves versus final cleanup. Privacy policySee how the app stays offline and how the website measurement is sanitized.

These notes describe the Centerline Android release available today.