Bb4 — 466.164 Hz
Bb4 (B-flat 4) is 466.164 Hz in standard equal temperament at A=440 Hz. It is MIDI note number 70.
Bb4 Frequency in All Tuning Systems
| Temperament | Frequency (Hz) | Cents from Equal | Common Usage |
|---|---|---|---|
| Equal Temperament | 466.164 Hz | 0.00 | Modern standard; piano, fretted instruments |
| Pythagorean | 463.538 Hz | -9.78 | Medieval/early music; string ensemble open fifths |
| Just Intonation (Major) | 470.926 Hz | +17.60 | A cappella vocal, barbershop, Renaissance |
| Just Intonation (Minor) | 470.926 Hz | +17.60 | Minor-key vocal music, string ensembles |
| Quarter-Comma Meantone | 470.794 Hz | +17.11 | Renaissance keyboard, early Baroque organ |
| Third-Comma Meantone | 472.256 Hz | +22.48 | Renaissance vocal music in minor keys |
| Sixth-Comma Meantone | 469.333 Hz | +11.73 | Baroque orchestral ensemble compromise |
| Werckmeister III | 469.333 Hz | +11.73 | Baroque keyboard; Bach contemporaries |
| Werckmeister IV | 468.805 Hz | +9.78 | Baroque keyboard, strong key contrast |
| Werckmeister V | 467.218 Hz | +3.91 | Specialized Baroque keyboard |
| Kirnberger III | 468.935 Hz | +10.26 | Classical-era keyboard, keys near C major |
| Vallotti | 467.747 Hz | +5.87 | Baroque/Classical orchestral tuning |
| Young (1799) | 468.274 Hz | +7.82 | Classical-era keyboard |
| Bach/Lehman | 467.747 Hz | +5.87 | Bach keyboard works, Well-Tempered Clavier |
| Neidhardt | 467.218 Hz | +3.91 | 18th century keyboard, near-equal alternative |
| Kellner (Bach) | 468.696 Hz | +9.38 | Bach keyboard reconstruction |
Positive cents = sharper than equal temperament. Negative cents = flatter. 100 cents = 1 semitone.
Bb4 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) | 466.164 Hz | US, UK, and most modern ensembles worldwide |
| A = 442 Hz | 468.283 Hz | Many European orchestras; France, Germany |
| A = 443 Hz | 469.342 Hz | Berlin Philharmonic; some US orchestras |
| A = 432 Hz | 457.688 Hz | Alternative tuning; Baroque revival |
| A = 415 Hz (Baroque) | 439.677 Hz | Historically-informed Baroque performance |
f = f_at_A440 × (concert_pitch / 440)
Instruments That Play Bb4
Bb4 (466.164 Hz) falls within the comfortable playing range of 44 instruments.
Bb4 and A#4 — Enharmonic Equivalents
Bb4 and A#4 are enharmonic equivalents — they sound identical at 466.164 Hz but are written differently depending on the musical context.
Bb4: B♭ appears as the tonic of B♭ major and is one of the most common flat notes in Western music. Common key signatures: B♭ major, E♭ major, F major.
A#4: A♯ appears in sharp key signatures and is the leading tone in B major. Common key signatures: B major, F♯ major, C♯ major.
Enharmonic equivalents share the same frequency in equal temperament. In historical temperaments like Pythagorean or meantone, they may differ slightly.
Why Bb4 Varies Across Tuning Systems
Bb4 shows a maximum deviation of +22.48 cents in Third-Comma Meantone compared to equal temperament. This 22-cent difference is clearly audible to trained musicians and reflects how different tuning philosophies prioritize interval purity over equal distribution.
In Third-Comma Meantone, Bb4 is tuned sharper than equal temperament to achieve purer intervals with nearby notes in the tuning system's favored keys.
7 of the 15 non-equal temperaments deviate by more than 10 cents for Bb4, making this note one where tuning system choice has a meaningful impact on pitch.
Bb4 Across All Tuning Systems
Explore how Bb4 is tuned in each historical temperament system. Each tuning system gives Bb4 a slightly different frequency, affecting the harmonic character of chords and melodies.
Tune Bb4 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.