Trombone Tuner icon

Not just “14 cents sharp.”

C3 · position 6 · push out ≈ 15 mm

Trombone Tuner is a tuner built for trombone. It knows which slide position you're in and tells you which way to move the slide — and how far.

Download on the App Store

↔️ Slide Coach

Every note gets a direction and a distance: push out, pull in, or hold. A zoomed ruler shows where your slide is against the target.

🎺 Knows the trombone

Alternate positions (tap to switch — it remembers), the flat 5th partial, and what to do when you're flat in 1st and can't pull in any further.

🔀 F attachment

Trigger positions on an F-attachment horn: C3 in T1, E2 in T2 — with the distances for the longer F side.

🎚️ Main-slide Tune-Up

Play B♭3 or F3 in 1st and hold it. Get “pull the main tuning slide out ≈ 6 mm” — and the F-attachment slide too.

〰️ Long tones

A live pitch trace, the share of the note within ±5 ¢, your drift, and a personal best for every note.

🎵 Drone & just intonation

Play against a drone (with headphones, the tuner keeps listening). In chords, aim 3rds about 14 ¢ low and 5ths 2 ¢ high.

How far is 10 cents?

Further out the slide, a semitone takes more tube — so the same pitch error needs a bigger move. On a typical B♭ tenor:

Position1st2nd3rd4th5th6th7th
10 ¢ ≈8 mm8 mm9 mm9 mm10 mm11 mm11 mm

Instruments differ slightly, so the app shows distances as approximate. The direction is what matters most — the distance gets you close.

Pay once

The chromatic tuner, position numbers and the slide chart are free forever, and the Slide Coach is free for your first three practice sessions. Pro — Slide Coach on every note, F-attachment positions, the Tune-Up, unlimited long tones, the drone and just intonation — is a one-time $6.99, shared with your family. No subscription.

Private by design

The microphone is used only to hear the note you're playing. Nothing is recorded, stored or sent anywhere. No account, no ads, no analytics.