528 Hz and 432 Hz: how they differ, and how they sound together

528 Hz and 432 Hz are different kinds of idea. 432 Hz is a tuning: the note A at 432 Hz, not the standard 440. 528 Hz is one tone, a Solfeggio number. No piano tuning has a note on both, so music is one or the other. The one trial comparing them, in 162 students, found small saliva differences and none in a thinking test.

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Pure 432 Hz tone Open in Studio

Open the 432 Hz page

Long ribbons of light flowing edge to edge across a dark field, deep yellow above for 528 Hz and gold below for 432 Hz — Illustration. One band of ribbons for each tone, the higher at the top. The middle ribbon of each band waves in proportion to its pitch: 11 waves of 528 Hz for every 9 of 432 Hz, the pair's own ratio.

What is the difference between 528 Hz and 432 Hz?

432 Hz is a tuning and 528 Hz is a tone. 432 Hz says where to set one note, the A above middle C, and every other note of a piece moves with it. 528 Hz is a single pitch: you can play it on its own, or tune music so that one of its notes lands on it.

The international standard sets that A at 440 Hz: ISO 16 says the note A in the treble stave "shall be 440 Hz". Tuning to 432 Hz lowers every note by 31.8 cents, about a third of a semitone, where a cent is a hundredth of a semitone. The 432 Hz guide tells the story of that choice, from what Verdi asked for to the claims made for it online.

528 Hz is one of the Solfeggio numbers, first printed in a 1999 book, Healing Codes for the Biological Apocalypse, by Leonard Horowitz and Joseph Puleo. The set names pitches, not a tuning: nothing in it says where the other notes of a piece should go. The 528 Hz guide follows where the number came from and what has been tested.

432 Hz and 528 Hz side by side: what each number names, where it comes from, how it sits on a piano and how often the two have been compared.

432 Hz and 528 Hz compared
Question	432 Hz	528 Hz
What it names	The note A, so a whole tuning	One pitch
Where it comes from	An alternative to the 440 Hz standard	The Solfeggio numbers, 1999
On a piano	Every note 31.8 cents below standard	A note only when A is 444 Hz
Compared head to head	Once: one trial, 162 students

Can music be tuned to 432 Hz and 528 Hz at once?

No. With A at 432 Hz, no note of the piano falls on 528 Hz: the nearest, a C, sits at 513.74 Hz, and 528 Hz is 47.4 cents above it, almost halfway to C sharp. Standard tuning misses too, with that C at 523.25 Hz, 15.6 cents below.

To make a note land on 528 Hz, the A has to go up, not down. A Japanese study of 528 Hz piano music sets it out: "In this musical scale, there is no 528 Hz note. However, setting the reference tone to 444 Hz means that 528 Hz is included in the musical scale." With A at 444 Hz, C sits at 528.01 Hz, and A at 443.993 Hz would put it there exactly.

Three rows for A at 432, 440 and 444 Hz: 528 Hz sits 47.4 cents above C, then 15.6 cents above C, then on C itself — With A at 432 Hz, 528 Hz falls 47.4 cents above C; with A at 440 Hz, 15.6 cents above it; only with A at 444 Hz does C land on 528 Hz.

So "432 Hz music" and "528 Hz music" ask for two different tunings, A at 432 Hz and A at 444 Hz, and those sit 47.4 cents apart, nearly half a semitone. A piece of music can follow one or the other, never both. The two numbers can still sound together, as two plain tones, and then the arithmetic takes over.

What happens when 432 Hz and 528 Hz play together?

Together, 432 Hz and 528 Hz make an interval a little wider than a minor third. The ratio 528 to 432 reduces to 11 to 9, which is 347.4 cents: between the minor third at 300 and the major third at 400. The Huygens-Fokker Foundation's list of musical intervals names 11:9 the undecimal neutral third.

Both numbers divide by 48: 432 is 9 times 48, and 528 is 11 times 48. So the two waves start together again every forty-eighth of a second, every 20.83 milliseconds, after exactly 9 waves of 432 Hz and 11 of 528 Hz.

Nine waves of 432 Hz and eleven of 528 Hz across 20.8 milliseconds, above their sum, which swells twice in that time — In every 20.83 milliseconds, 9 waves of 432 Hz meet 11 of 528 Hz, and their sum swells twice: 96 times a second, the gap between the two tones.

Whether a pair like this sounds smooth or rough depends on that gap and on the ear's critical band, the stretch of the inner ear that one tone sets moving. In a classic study, Plomp and Levelt found that listeners judged two plain tones consonant once they were more than a critical band apart, and most dissonant when they were about a quarter of a band apart.

Midway between the two tones, at 480 Hz, the band is about 77 Hz wide by Glasberg and Moore's formula, 24.7 × (0.00437 f + 1), which hearing scientists use today, and about 100 Hz by the older measure from Zwicker that Plomp and Levelt worked with. At 96 Hz apart, 432 Hz and 528 Hz sit 1.25 bands apart on the first count and just under one band on the second: at the smooth end of the scale, close to where roughness fades out. Even their faint overtones keep their distance. The nearest two, 864 and 1,056 Hz, are 192 Hz apart, about one and a half bands.

Can your ear add a third tone to 432 Hz and 528 Hz?

It can, faintly. When two tones sound together, the ear itself makes tones that are not in the air, called combination tones. The one heard most is twice the lower tone minus the higher: for this pair, twice 432 minus 528, which is 336 Hz. In Goldstein's experiments, its level relative to the pair hardly changed as the sound got louder, but fell sharply as the two tones moved apart, so with a pair this wide it is quiet at best. The plain difference tone, 528 minus 432, or 96 Hz, was heard only at high levels, above 50 dB sensation level, and combination tones above the pair were not heard at all.

This pair's ratio also matches the one at which the ear's own version of that tone was found strongest. The inner ear sends a faint sound back out at twice the lower tone minus the higher, and Harris and colleagues found that "an f2/f1 ratio of 1.22 was most effective" in making it loud. 528 divided by 432 is 1.222. Their tests used tones from 1 to 4 kHz, above this pair, so the match is one of ratio, not a measurement at these pitches.

What the sound itself holds is easy to check. At 336 Hz and at 96 Hz, the mix of the two tones Harmonance plays measures 82 and 86 dB below the tones, which is the noise floor of the decoding itself. If you hear anything at those pitches, it comes from your own hearing, or from the speaker playing the sound.

What is in Harmonance's 432 Hz and 528 Hz tones?

The 432 Hz and 528 Hz pages each play a 20 second loop. Harmonance measured the two files mixed sample for sample, as if both played at once. The two strongest lines sit at 432.000 and 528.000 Hz, at exactly the same level. Above each tone sit two faint overtones, its second harmonic 23.1 dB down and its third 34 dB down, and nothing else in the files comes within 57.2 dB of the tones.

Bars for each line in the two tones played together: both tones at full level, overtones 23.1 and 34 dB down, nothing at 96 or 336 Hz — Played together, Harmonance's 432 Hz and 528 Hz files hold the two tones at equal level and their faint second and third harmonics, 23.1 and 34 dB down; at 96 and 336 Hz, where the ear can add tones, they hold nothing.

The numbers behind the chart
Line	What it is	Below the tones
432 Hz	the 432 Hz tone	0 dB
528 Hz	the 528 Hz tone	0 dB
864 Hz	second harmonic of 432 Hz	23.1 dB
1,056 Hz	second harmonic of 528 Hz	23.1 dB
1,296 Hz	third harmonic of 432 Hz	34.0 dB
1,584 Hz	third harmonic of 528 Hz	34.0 dB
336 Hz	not in the files: where the ear can add a tone	82.1 dB, the noise floor
96 Hz	not in the files: the difference tone's place	86.4 dB, the noise floor

Download the measurements (CSV)

So the pages play two near-pure tones at the same level, with overtones far enough down to stay in the background. Each tone also plays with Strings on its own page, where strings tuned to the tone carry the music and the exact tone sits underneath.

What do studies show about 528 Hz and 432 Hz?

One trial has set 528 Hz music and 432 Hz music against each other, and what it measured was saliva, not how anyone felt. Researchers in Ankara gave 162 healthy university students, 54 to a group, either silence or 20 minutes of "528 Hz" or "432 Hz" instrumental music through headphones, during an exam period (Bozok and colleagues, 2026). Straight after, they took saliva samples and gave the Stroop test, which times how fast you name the ink colour of a printed colour word.

The trial's saliva markers after silence or 20 minutes of music, as medians in nanograms per millilitre: CREB was highest after the 528 Hz music, and GRP78 highest after the 432 Hz music.

Saliva markers by group
Marker	Silence	432 Hz music	528 Hz music
BDNF	3.54	2.88	3.84
CREB	1.13	1.06	1.50
GRP78	0.45	0.51	0.44

The three markers are proteins. BDNF and CREB are studied for their part in learning and memory, and GRP78 as a sign of strain. After the 528 Hz music, CREB was higher than in either other group. After the 432 Hz music, GRP78 was higher and BDNF lower. On BDNF the paper disagrees with itself: its summary says 528 Hz music raised it, while its own table and conclusion put the 528 Hz group level with silence. The Stroop test showed no difference between any of the groups.

What the trial does not show is just as clear. The authors call it a pilot, run "to generate prospective hypotheses". The paper never says what music was played, how it was tuned or how loud it was, so it cannot tell a tuning apart from two different pieces of music. Markers in saliva, measured straight after 20 minutes, are not feelings or health, and the one test of thinking found nothing.

Two smaller studies tested each number against standard tuning, not against each other. In Italy, 33 volunteers heard the same film music tuned to 440 Hz on one day and to 432 Hz on another, 20 minutes each, and their heart rate averaged 4.79 beats a minute lower with 432 Hz, right on the usual line for chance at p = 0.05 (Calamassi and Pomponi, 2019). The authors start from the point that "there are no scientific studies that support this hypothesis", and close by asking for larger randomised trials. In Japan, nine adults heard five minutes of piano music tuned to put 528 Hz on a note, and on another day the same music at 440 Hz; the cortisol in their saliva fell significantly over the next 30 minutes only after the 528 Hz version (Akimoto and colleagues, 2018).

That is small samples, different measures and no repeat, and research on music as a whole is at the same early stage. The US National Center for Complementary and Integrative Health sums it up:

However, because much of the research on music-based interventions is preliminary, few definite conclusions about their effects have been reached.

Is 432 Hz or 528 Hz better?

Neither has been shown to be better than the other. The one head-to-head trial found differences in saliva and none in a thinking test, with music it never described, and nobody has repeated it. No study has played the two tones together at all. What is certain is plainer: 528 Hz sits 96 Hz above 432 Hz, and together they make a smooth interval, not a rough one.

So choose by ear. Play 432 Hz for a few minutes at a low volume, then 528 Hz, and notice which one you come back to. Keep the volume low either way: loud listening is the one risk that is well established, and the NCCIH notes that "listening to music at too high a volume can contribute to noise-induced hearing loss".

How do you play 432 Hz and 528 Hz on Harmonance?

Press play at the top of this guide to hear 432 Hz, or open the 432 Hz page and the 528 Hz page. Each plays its tone alone, or with Strings switched on, strings tuned to the tone with the exact tone underneath. Nothing plays until you press play, and no account is needed.

To hear the two together, open Harmonance Studio, the free Harmonance instrument, which plays several tones at once after you sign in with a free account: add 432 Hz and 528 Hz, then balance them by ear. The Need to unwind page gathers 432 Hz with other tones people reach for at the end of a day, and the Solfeggio collection plays 528 Hz with the rest of its set.

For another set of numbers heard together, the guide to 174, 417 and 741 Hz works through three Solfeggio tones at once, and what the science of sound healing shows sets out what research on sound has and has not found.

Sources and limits

The comparison rests on arithmetic anyone can redo, the international standard for pitch and classic papers on hearing. The research is thin: one head-to-head trial, which calls itself a pilot and does not describe its music, and two smaller studies, each of one number against standard tuning. No study has played 432 Hz and 528 Hz together. The measurements of the two tone files are Harmonance's own, made from the files the pages play.