C#2 — 69.296 Hz
C#2 (C-sharp 2) is 69.296 Hz in standard equal temperament at A=440 Hz. It is MIDI note number 37.
C#2 Frequency in All Tuning Systems
| Temperament | Frequency (Hz) | Cents from Equal | Common Usage |
|---|---|---|---|
| Equal Temperament | 69.296 Hz | 0.00 | Modern standard; piano, fretted instruments |
| Pythagorean | 69.609 Hz | +7.80 | Medieval/early music; string ensemble open fifths |
| Just Intonation (Major) | 69.767 Hz | +11.73 | A cappella vocal, barbershop, Renaissance |
| Just Intonation (Minor) | 69.767 Hz | +11.73 | Minor-key vocal music, string ensembles |
| Quarter-Comma Meantone | 68.750 Hz | -13.69 | Renaissance keyboard, early Baroque organ |
| Third-Comma Meantone | 68.595 Hz | -17.60 | Renaissance vocal music in minor keys |
| Sixth-Comma Meantone | 68.910 Hz | -9.67 | Baroque orchestral ensemble compromise |
| Werckmeister III | 69.374 Hz | +1.95 | Baroque keyboard; Bach contemporaries |
| Werckmeister IV | 69.061 Hz | -5.88 | Baroque keyboard, strong key contrast |
| Werckmeister V | 69.374 Hz | +1.95 | Specialized Baroque keyboard |
| Kirnberger III | 69.315 Hz | +0.47 | Classical-era keyboard, keys near C major |
| Vallotti | 69.374 Hz | +1.95 | Baroque/Classical orchestral tuning |
| Young (1799) | 69.374 Hz | +1.95 | Classical-era keyboard |
| Bach/Lehman | 69.452 Hz | +3.89 | Bach keyboard works, Well-Tempered Clavier |
| Neidhardt | 69.374 Hz | +1.95 | 18th century keyboard, near-equal alternative |
| Kellner (Bach) | 69.374 Hz | +1.95 | Bach keyboard reconstruction |
Positive cents = sharper than equal temperament. Negative cents = flatter. 100 cents = 1 semitone.
C#2 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) | 69.296 Hz | US, UK, and most modern ensembles worldwide |
| A = 442 Hz | 69.611 Hz | Many European orchestras; France, Germany |
| A = 443 Hz | 69.768 Hz | Berlin Philharmonic; some US orchestras |
| A = 432 Hz | 68.036 Hz | Alternative tuning; Baroque revival |
| A = 415 Hz (Baroque) | 65.358 Hz | Historically-informed Baroque performance |
f = f_at_A440 × (concert_pitch / 440)
Instruments That Play C#2
C#2 (69.296 Hz) falls within the comfortable playing range of 17 instruments.
C#2 and Db2 — Enharmonic Equivalents
C#2 and Db2 are enharmonic equivalents — they sound identical at 69.296 Hz but are written differently depending on the musical context.
C#2: C♯ appears in sharp key signatures and is the leading tone in D major. Common key signatures: A major, E major, B major, F♯ major, C♯ major.
Db2: D♭ appears as the tonic of D♭ major and is common in flat key signatures. Common key signatures: D♭ major, G♭ major, A♭ major.
Enharmonic equivalents share the same frequency in equal temperament. In historical temperaments like Pythagorean or meantone, they may differ slightly.
Why C#2 Varies Across Tuning Systems
C#2 shows a maximum deviation of -17.60 cents in Third-Comma Meantone compared to equal temperament. This 18-cent difference is clearly audible to trained musicians and reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Third-Comma Meantone, C#2 is tuned flatter than equal temperament, reflecting this system's approach to distributing the Pythagorean comma across the chromatic scale.
4 of the 15 non-equal temperaments deviate by more than 10 cents for C#2, making this note one where tuning system choice has a meaningful impact on pitch.
C#2 Across All Tuning Systems
Explore how C#2 is tuned in each historical temperament system. Each tuning system gives C#2 a slightly different frequency, affecting the harmonic character of chords and melodies.
Tune C#2 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.