If the display moves after you pluck a string, the tuner is not necessarily inaccurate. The pitch of a real instrument changes slightly over time, and the microphone captures harmonics and room noise along with the fundamental note.
A musical note is not a single frequency
When a guitar plays an A, you hear a fundamental along with partials near multiples of that frequency. Microphone position and playing technique can make a harmonic louder than the fundamental. A pitch detector must estimate the note we perceive from this complex signal.
Read the display after the initial attack
The moment a pick hits the string contains wideband transient noise. A hard pluck can also increase string tension briefly, causing the pitch to start sharp and settle downward. Wait roughly half a second to one second, then read the display during the stable part of the note.
Create a stable tuning environment
- Lightly mute the strings you are not tuning.
- Keep the phone microphone at a moderate distance from the instrument.
- Reduce continuous noise from televisions, fans, and conversations.
- Play one note at a time with consistent force.
- Hold a guitar in your normal playing position while tuning.
Repeating the note at a medium volume is usually more reliable than striking it once as hard as possible.
What are cents?
A cent is one hundredth of a semitone. If the tuner shows +8 cents, the note is slightly above its target. Small movements are normal: finger pressure, temperature, and even playing position can change pitch by a few cents.
When is a harmonic mode useful?
Low strings and instruments with strong overtones can make the fundamental difficult to detect. A harmonic can provide a clearer component that still reflects the tuning of the same string. Use it only when you know which harmonic and target note you are checking.
AcuTune’s real-time display shows the movement already present in the instrument instead of hiding it. The goal is not to freeze the needle forever. It is to make the stable portion of each note pass through the center consistently.