Solfeggio frequency
639 Hz — Solfeggio Frequency (“FA”)
639 Hz is the Solfeggio tone labelled “FA”, in the upper-mid range near the note D#5.
Tap a note to play its exact pitch — C1 to B8
Press Space to play
About the 639 Hz tone
639 Hz is a brighter, more present tone than the lower Solfeggio frequencies, which makes it easy to pick out when layered under music.
This page plays it as a steady sine wave. We keep the description factual and make no claims — adjust the waveform and volume to whatever suits you.
By pitch, 639 Hz is closest to D#5 (the E-flat in the octave above middle C), sitting a little below it — the generator gives the exact note and cents. Being an upper-mid tone, it cuts through a mix more than 396 or 417 Hz, so it works well as the top layer of a Solfeggio drone with lower tones underneath. Its octave down is roughly 319.5 Hz and its octave up 1278 Hz if you want to spread the same pitch across the range.
Technical details
- Frequency
- 639 Hz
- Nearest note
- D#5 (+46¢)
- Category
- Solfeggio frequency
- Period
- 1.56 ms
- Wavelength (air)
- 53.7 cm
- Octave up / down
- 1278 Hz / 319.5 Hz
Common uses
- An upper-mid tone for ambient or meditation layering
- Combine with 396 and 528 Hz from the same series
- Ear-training reference near the note D#5
Frequently asked questions
What note is 639 Hz?
639 Hz is closest to D#5 (E-flat above middle C), sitting slightly below it. The generator shows the nearest note and the exact cents difference so you can place it on a keyboard or tuner.
Is 639 Hz a Solfeggio frequency?
Yes — it’s the fourth of the six traditional Solfeggio tones, labelled “FA”, in the upper-mid part of the series above 528 Hz and below 741 Hz.
What’s the difference between 639 Hz and 528 Hz?
639 Hz is higher and brighter; 528 Hz is lower and closer to C5. They’re neighbouring tones in the same series, so the easiest way to compare is to open each from the Nearby frequencies links and switch between them.