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About D♯7
D♯7 / E♭7 has a frequency of 2.489 kHz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 99 and key number 79 on an 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so D♯7 is 30 semitones above A4: f = 440 × 2^((99 − 69) / 12) = 2,489.02 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
D♯7 and E♭7 are enharmonic: on a piano or in equal temperament they are the same key and the same frequency, but they are spelled differently depending on the key signature.
D♯7 frequency in different tunings
| Tuning reference | D♯7 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 2.489 kHz |
| A4 = 442 Hz (many European orchestras) | 2.5 kHz |
| A4 = 443 Hz (Berlin, Vienna) | 2.506 kHz |
| A4 = 435 Hz (French diapason normal, 1859) | 2.461 kHz |
| A4 = 432 Hz (alternative tuning) | 2.444 kHz |
| A4 = 415 Hz (Baroque pitch) | 2.348 kHz |
| C4 = 256 Hz (scientific pitch) | 2.435 kHz |
Intervals from D♯7
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | E7 | 2.637 kHz | 16:15 |
| Major second | F7 | 2.794 kHz | 9:8 |
| Minor third | F♯7 | 2.96 kHz | 6:5 |
| Major third | G7 | 3.136 kHz | 5:4 |
| Perfect fourth | G♯7 | 3.322 kHz | 4:3 |
| Tritone | A7 | 3.52 kHz | 45:32 |
| Perfect fifth | A♯7 | 3.729 kHz | 3:2 |
| Minor sixth | B7 | 3.951 kHz | 8:5 |
| Major sixth | C8 | 4.186 kHz | 5:3 |
| Minor seventh | C♯8 | 4.435 kHz | 9:5 |
| Major seventh | D8 | 4.699 kHz | 15:8 |
| Octave | D♯8 | 4.978 kHz | 2:1 |
Instruments and voices that can play D♯7
Frequently asked questions
What is the frequency of D♯7?
D♯7 is 2.489 kHz when A4 = 440 Hz (2.444 kHz if A4 = 432 Hz).
What MIDI number is D♯7?
D♯7 is MIDI note number 99.
Is D♯7 on a piano?
Yes – it is key 79 of 88.