36.71Hz
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36.71 HzFrequency at A4 = 440 Hz
26MIDI note number
6Piano key (of 88)
9.34 mWavelength in air
About D1
D1 has a frequency of 36.71 Hz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 26 and key number 6 on an 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so D1 is 43 semitones below A4: f = 440 × 2^((26 − 69) / 12) = 36.71 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
D1 frequency in different tunings
| Tuning reference | D1 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 36.71 Hz |
| A4 = 442 Hz (many European orchestras) | 36.87 Hz |
| A4 = 443 Hz (Berlin, Vienna) | 36.96 Hz |
| A4 = 435 Hz (French diapason normal, 1859) | 36.29 Hz |
| A4 = 432 Hz (alternative tuning) | 36.04 Hz |
| A4 = 415 Hz (Baroque pitch) | 34.62 Hz |
| C4 = 256 Hz (scientific pitch) | 35.92 Hz |
Intervals from D1
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | D♯1 | 38.89 Hz | 16:15 |
| Major second | E1 | 41.2 Hz | 9:8 |
| Minor third | F1 | 43.65 Hz | 6:5 |
| Major third | F♯1 | 46.25 Hz | 5:4 |
| Perfect fourth | G1 | 49 Hz | 4:3 |
| Tritone | G♯1 | 51.91 Hz | 45:32 |
| Perfect fifth | A1 | 55 Hz | 3:2 |
| Minor sixth | A♯1 | 58.27 Hz | 8:5 |
| Major sixth | B1 | 61.74 Hz | 5:3 |
| Minor seventh | C2 | 65.41 Hz | 9:5 |
| Major seventh | C♯2 | 69.3 Hz | 15:8 |
| Octave | D2 | 73.42 Hz | 2:1 |
Instruments and voices that can play D1
Frequently asked questions
What is the frequency of D1?
D1 is 36.71 Hz when A4 = 440 Hz (36.04 Hz if A4 = 432 Hz).
What MIDI number is D1?
D1 is MIDI note number 26.
Is D1 on a piano?
Yes – it is key 6 of 88.