调音检查与新弦的稳定期

Why a ukulele goes out of tune so fast

Four short, light nylon strings at low tension: the physics is against you. Nylon stretches for days after it is fitted, the small body responds to every change in room temperature, and the short scale means a tiny slip in tension moves the pitch further than it would on a guitar.

The habit that fixes most of it: tune up to pitch, never down. If a string is sharp, drop it below the note and come back up. Coming up to pitch leaves the string wound tight against the post; coming down leaves it loose and it will drift the moment you play a chord.

The five-point check before you play

1. Open strings with a tuner, G C E A, tuning up to pitch each time.
2. Fifth fret of the G string should equal the open C string. If it is sharp, the string is too high at the nut.
3. Fourth fret of the C string should equal the open E string.
4. Fourth fret of the E string should equal the open A string.
5. Twelfth fret harmonic should equal the open string. If the twelfth fret is sharp, the saddle needs adjusting; if it is flat, the string is old.

Steps 2 to 4 catch a bad nut, a worn string or a slipped tuning peg in thirty seconds without any equipment.

Letting new strings settle

A fresh set needs two to four days of playing before it holds pitch for a whole song. Three things speed that up:

• Stretch gently. After tuning, pull each string about 2 cm away from the fretboard and let it snap back, then retune. Repeat three times. This is safe on nylon and does more than anything else.
• Play, then retune. Tune, play a song, retune. Four cycles in the first hour is normal.
• Check the knots. A slipping bridge knot is the most common cause of a string that goes flat every few minutes. Pull the knot tight against the bridge and re-tune.

When to change strings

Nylon strings go dead rather than break. The signs: the fourth string sounds dull, intonation at the twelfth fret goes sharp, and the string develops flat spots where the frets touch. For daily playing, a new set every two to three months; for occasional playing, twice a year.