C#2 — 69.30 Hz
C#2 (MIDI 37) vibrates 69.30 times per second at standard concert pitch. Play the reference tone below, or tune to it with the online tuner.
C#2 at different reference pitches
| Reference (A4) | C#2 frequency | Used for |
|---|---|---|
| 415 Hz | 65.36 Hz | Baroque pitch |
| 432 Hz | 68.04 Hz | “Verdi” pitch |
| 440 Hz | 69.30 Hz | Standard concert pitch |
| 442 Hz | 69.61 Hz | European orchestras |
| 444 Hz | 69.93 Hz | European orchestras |
Physical properties
- Period: one cycle every 14.43 ms
- Wavelength in air: ≈ 4.95 m (at 20 °C, 343 m/s)
- MIDI note number: 37
- Octave up: C#3 = 138.59 Hz · Octave down: 34.65 Hz