C2 — 65.406 Hz
C2 (C2) is 65.406 Hz in standard equal temperament at A=440 Hz. It is MIDI note number 36.
C2 Frequency in All Tuning Systems
| Temperament | Frequency (Hz) | Cents from Equal | Common Usage |
|---|---|---|---|
| Equal Temperament | 65.406 Hz | 0.00 | Modern standard; piano, fretted instruments |
| Pythagorean | 65.185 Hz | -5.86 | Medieval/early music; string ensemble open fifths |
| Just Intonation (Major) | 65.406 Hz | 0.00 | A cappella vocal, barbershop, Renaissance |
| Just Intonation (Minor) | 65.406 Hz | 0.00 | Minor-key vocal music, string ensembles |
| Quarter-Comma Meantone | 65.795 Hz | +10.27 | Renaissance keyboard, early Baroque organ |
| Third-Comma Meantone | 65.926 Hz | +13.71 | Renaissance vocal music in minor keys |
| Sixth-Comma Meantone | 65.666 Hz | +6.87 | Baroque orchestral ensemble compromise |
| Werckmeister III | 65.851 Hz | +11.74 | Baroque keyboard; Bach contemporaries |
| Werckmeister IV | 65.703 Hz | +7.84 | Baroque keyboard, strong key contrast |
| Werckmeister V | 65.629 Hz | +5.89 | Specialized Baroque keyboard |
| Kirnberger III | 65.795 Hz | +10.27 | Classical-era keyboard, keys near C major |
| Vallotti | 65.629 Hz | +5.89 | Baroque/Classical orchestral tuning |
| Young (1799) | 65.703 Hz | +7.84 | Classical-era keyboard |
| Bach/Lehman | 65.629 Hz | +5.89 | Bach keyboard works, Well-Tempered Clavier |
| Neidhardt | 65.554 Hz | +3.91 | 18th century keyboard, near-equal alternative |
| Kellner (Bach) | 65.762 Hz | +9.40 | Bach keyboard reconstruction |
Positive cents = sharper than equal temperament. Negative cents = flatter. 100 cents = 1 semitone.
C2 at Different Concert Pitches
The same note varies in frequency depending on the concert pitch standard used by your ensemble.
| Concert Pitch | Frequency (Hz) | Common Usage |
|---|---|---|
| A = 440 Hz (ISO standard) | 65.406 Hz | US, UK, and most modern ensembles worldwide |
| A = 442 Hz | 65.704 Hz | Many European orchestras; France, Germany |
| A = 443 Hz | 65.852 Hz | Berlin Philharmonic; some US orchestras |
| A = 432 Hz | 64.217 Hz | Alternative tuning; Baroque revival |
| A = 415 Hz (Baroque) | 61.690 Hz | Historically-informed Baroque performance |
f = f_at_A440 × (concert_pitch / 440)
Instruments That Play C2
C2 (65.406 Hz) falls within the comfortable playing range of 16 instruments.
Why C2 Varies Across Tuning Systems
C2 shows a maximum deviation of +13.71 cents in Third-Comma Meantone compared to equal temperament. This 14-cent difference reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Third-Comma Meantone, C2 is tuned sharper than equal temperament to achieve purer intervals with nearby notes in the tuning system's favored keys.
4 of the 15 non-equal temperaments deviate by more than 10 cents for C2, making this note one where tuning system choice has a meaningful impact on pitch.
C2 Across All Tuning Systems
Explore how C2 is tuned in each historical temperament system. Each tuning system gives C2 a slightly different frequency, affecting the harmonic character of chords and melodies.
Tune C2 with precision — Get Tunable.
Tunable supports 15+ tuning systems including equal temperament, Pythagorean, just intonation, and historical well-temperaments. See exact Hz values in real-time as you play.