How A440 affects guitar strings
The open fifth string is A2 at 110 Hz, two octaves below A4. Standard E, D, G, B, and E pitches are mathematically related to the same reference, so changing calibration shifts every target together.
Reference pitch is not the tuning pattern
E A D G B E describes interval relationships and note names. A440 describes calibration. A guitar can use standard tuning at A432, A440, or A444 while retaining the same note sequence.
When to change calibration
Use A440 unless playing with a recording, ensemble, piano, or instrument calibrated differently. If a song is slightly off concert pitch, match that reference rather than forcing ordinary A440 targets.
Step-by-step check
- Select the Standard — E A D G B E preset.
- Tune E A D G B E normally.
- Compare with the fixed-pitch instrument or recording.
- Change reference only when there is a clear reason.
- Return to A440 for ordinary practice with modern instruments.
Reliable tuning habits
Work with one string at a time, use a moderate and repeatable picking attack, and let the initial pitch settle briefly. Make the final adjustment by approaching the target from below so slack is taken out of the tuning post and nut. After all six strings are close, repeat the entire pass because every tension change can slightly affect the other strings.