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 Tuning | 65.185 Hz | -5.86 | Medieval/early music; string ensemble open fifths |
| Just / Pure | 65.406 Hz | 0.00 | A cappella vocal, barbershop, Renaissance |
| Meantone 1/3 Comma | 65.926 Hz | +13.71 | Renaissance vocal music in minor keys |
| Meantone 1/4 Comma | 65.795 Hz | +10.27 | Renaissance keyboard, early Baroque organ |
| 1/6 SC - Attenuated | 65.666 Hz | +6.87 | Baroque orchestral ensemble compromise |
| Kellner's Bach | 65.762 Hz | +9.40 | Bach keyboard reconstruction |
| Kirnberger III | 65.795 Hz | +10.27 | Classical-era keyboard, keys near C major |
| Vallotti | 65.629 Hz | +5.89 | Baroque/Classical orchestral tuning |
| 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 |
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 Meantone 1/3 Comma compared to equal temperament. This 14-cent difference reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Meantone 1/3 Comma, 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.
C2 in Historical Temperament Systems
Explore how C2 (65.406 Hz in equal temperament) is tuned in each of the 15 historical non-equal temperament systems. Each system places C2 at a slightly different frequency based on its mathematical basis.
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.
