Re or D is the second note of the solfege. When calculated in equal temperament with a reference of A above middle C as 440 Hz, the frequency of the D note is approximately 293.665 Hz. See pitch for a discussion of historical variations in frequency.
Designation by octave
| Scientific Designation |
Helmholtz Designation |
Octave Name |
Frequency (Hz) |
| D-1 |
Dˌˌˌ |
Subsubcontra |
9.177 |
| D0 |
Dˌˌ |
Subcontra |
18.354 |
| D1 |
Dˌ |
Contra |
36.708 |
| D2 |
D |
Great |
73.416 |
| D3 |
d |
Small |
146.832 |
| D4 |
d′ |
One-lined |
293.665 |
| D5 |
d″ |
Two-lined |
587.33 |
| D6 |
d′″ |
Three-lined |
1174.659 |
| D7 |
d″″ |
Four-lined |
2349.318 |
| D8 |
d′″″ |
Five-lined |
4698.636 |
| D9 |
d″″″ |
Six-lined |
9397.273 |
