Question 1

What does A4=440Hz mean?

Accepted Answer

A4=440Hz is the international standard tuning reference, meaning the A above middle C vibrates at 440 Hz. Established in 1939, it is the global standard for musical tuning used by most instruments and music production.

Question 2

How is note frequency calculated?

Accepted Answer

Note frequencies follow a geometric progression. Each octave (12 semitones) doubles the frequency. Formula: f = 440 × 2^(n/12), where n is the number of semitones from A4. For example, C5 is 3 semitones above A4, so f = 440×2^(3/12) ≈ 523.25Hz.

Question 3

What note naming systems are supported?

Accepted Answer

Three systems: 1) Scientific pitch notation (e.g., C4, A4) — recommended; 2) Helmholtz notation (e.g., c', a'); 3) MIDI note numbers (0-127). C4 = MIDI 60 = middle C.

Question 4

Why use tunings other than 440Hz?

Accepted Answer

While 440Hz is standard, some orchestras use 441Hz, 442Hz, or 443Hz for a brighter sound. Baroque music often uses 415Hz, and Classical period music uses 430Hz. This calculator supports custom reference frequencies.

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