D2
73.416Hz at concert pitch
Press to hear a pure sine tone at this pitch.
MIDI note
38
Piano key
18
Octave
2
Frequency
73.416 Hz
Period
13.621 ms
Wavelength
4.672 m
Pitch class
D
Notation
SPN
MIDI is the note number synths and software pass around (0–127). Pitch class is the note without its octave — all the Ds share one.
At other reference pitches
| Reference (A4) | D2 frequency | Where you meet it |
|---|---|---|
| 432 Hz | 72.081 Hz | the alternative-tuning circle |
| 440 Hzstandard | 73.416 Hz | the ISO 16 standard — concert pitch |
| 442 Hz | 73.75 Hz | many European orchestras tune a touch sharp |
| 443 Hz | 73.917 Hz | some sharper continental orchestras |
Every row is D2 — only the A4 you tune to changes. A frequency scales straight with the reference: D2 at 432 Hz is the 440 Hz value times 432⁄440.
Move around
Every D
Chords with D in them
D appears in each of these — see the whole chord grid.