73.42Hz
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73.42 HzFrequency at A4 = 440 Hz
38MIDI note number
18Piano key (of 88)
4.67 mWavelength in air
About D2
D2 has a frequency of 73.42 Hz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 38 and key number 18 on an 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so D2 is 31 semitones below A4: f = 440 × 2^((38 − 69) / 12) = 73.42 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
D2 frequency in different tunings
| Tuning reference | D2 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 73.42 Hz |
| A4 = 442 Hz (many European orchestras) | 73.75 Hz |
| A4 = 443 Hz (Berlin, Vienna) | 73.92 Hz |
| A4 = 435 Hz (French diapason normal, 1859) | 72.58 Hz |
| A4 = 432 Hz (alternative tuning) | 72.08 Hz |
| A4 = 415 Hz (Baroque pitch) | 69.24 Hz |
| C4 = 256 Hz (scientific pitch) | 71.84 Hz |
Intervals from D2
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | D♯2 | 77.78 Hz | 16:15 |
| Major second | E2 | 82.41 Hz | 9:8 |
| Minor third | F2 | 87.31 Hz | 6:5 |
| Major third | F♯2 | 92.5 Hz | 5:4 |
| Perfect fourth | G2 | 98 Hz | 4:3 |
| Tritone | G♯2 | 103.83 Hz | 45:32 |
| Perfect fifth | A2 | 110 Hz | 3:2 |
| Minor sixth | A♯2 | 116.54 Hz | 8:5 |
| Major sixth | B2 | 123.47 Hz | 5:3 |
| Minor seventh | C3 | 130.81 Hz | 9:5 |
| Major seventh | C♯3 | 138.59 Hz | 15:8 |
| Octave | D3 | 146.83 Hz | 2:1 |
Instruments and voices that can play D2
Frequently asked questions
What is the frequency of D2?
D2 is 73.42 Hz when A4 = 440 Hz (72.08 Hz if A4 = 432 Hz).
What MIDI number is D2?
D2 is MIDI note number 38.
Is D2 on a piano?
Yes – it is key 18 of 88.