A=415 Hz Concert Pitch — Note Frequencies

About A=415 Hz

A=415 Hz is the standard concert pitch for historically-informed performance (HIP) of Baroque music. It sits approximately 89.7 cents below A=440 Hz — nearly one equal-tempered semitone flat. This pitch level is derived from the study of surviving Baroque woodwind and brass instruments, which were built and sized to resonate at this lower reference pitch.

The A=415 standard corresponds to the pitch level used in much of the repertoire of J.S. Bach, G.F. Handel, Antonio Vivaldi, and their contemporaries. Baroque organs, harpsichords, and continuo instruments preserved in museums often measure close to A=415 Hz when maintained at period conditions. Modern HIP ensembles adopt this reference to achieve the tonal balance and key relationships intended by composers of the period.

Performing at A=415 Hz on modern instruments typically requires transposing one semitone — for example, a clarinet player in a Baroque ensemble may use a different instrument or adapt fingerings. Strings can be retuned directly. Keyboard instruments must be completely retuned or rebuilt for period pitch. The audible effect on ensemble colour is significant: everything sounds approximately a semitone lower and slightly darker than modern A=440 pitch.

Chromatic Note Frequencies at A=415 Hz

All 12 chromatic notes in equal temperament, calculated at A=415 Hz reference pitch across octaves 3, 4, and 5. Hz values are rounded to 3 decimal places.

Frequencies computed from f = 415 × 2^{(MIDI − 69) / 12} where A4 MIDI = 69. The highlighted row is A, the concert pitch reference note at this standard.

Other Concert Pitch Standards

• A=440 Hz — ISO Standard (1939)
• A=432 Hz — Alternative Tuning
• A=442 Hz — European Orchestral
• A=443 Hz — High European / Asian Orchestral

Related Reference Pages

• A4 note page — full temperament frequency data
• Note frequency hub — all 153 notes
• Concert pitch hub — compare all 5 standards