How to play String Tuner
- Choose a test and read the string's length, the wave speed, or the note on the card.
- A string fixed at both ends is half a wavelength long: f = v ÷ (2·L), and T = 1 ÷ f.
- Type your prediction and press Start. The string vibrates slowed down; the tuner shows its real frequency.
- Compare the orange needle with the blue one, or your finger's place with the note wanted.
Frequency and pitch
The frequency of a vibration is how many times it repeats each second, in hertz (Hz), and for a sound it is the pitch you hear: the faster the vibration, the higher the note. A plucked string is held still at both ends, so it vibrates as a standing wave, and the simplest way is a single hump: half a wave. Its wavelength is therefore twice the vibrating length, λ = 2·L, and since waves travel along the string at a speed v, the frequency is f = v ÷ (2·L). Three things set the note. The length: halve it and the frequency doubles, which musicians call an octave; frets let you shorten a string exactly. The tension: tighter strings carry waves faster, as v = √(F ÷ μ), so four times the tension doubles the frequency; that's tuning. And the mass per metre μ: thick strings carry waves slowly and play low. The period T = 1 ÷ f is the time for one vibration: a 220 Hz string completes one every 4.5 thousandths of a second.
A focused learning model
The string is ideal: perfectly flexible, fixed at the nut (or your finger) and the bridge, and vibrating only in its simplest mode, one half-wave, with no damping. The motion is shown slowed down by its own frequency, so one vibration lasts one second on screen; the height of the vibration is enlarged. Pressing the string doesn't change its tension. Answers within 2% are right.