174 Hz benefits: the claims and what is known

174 Hz is the lowest of the nine Solfeggio frequencies, linked online with comfort, grounding and a sense of safety, and often called a natural anaesthetic. No study shows any of these benefits, and the number joined the set after 1999. When 37 adults rated how twelve pure tones sounded, 174 Hz came out the calmest of the nine Solfeggio tones, as low tones generally did.

Ready to play Comfort And Grounding 174 Hz

Settle into a comfortable place and listen.

Pure 174 Hz tone Open in Studio

Open the 174 Hz page

Long brown-red ribbons of light flowing in gentle waves from edge to edge across a deep, dark field — Illustration. The Harmonance wave field in the brown-red of 174 Hz. The field draws a lower tone with longer waves, and 174 Hz is the lowest of the nine Solfeggio tones.

What are the claimed benefits of 174 Hz?

The benefits claimed for 174 Hz are about comfort and safety. Online it is called a grounding tone and a tone of security, and it is often described as a natural anaesthetic. Some sites pair it with the root chakra as well, although the usual Solfeggio chakra map gives the root 396 Hz and leaves 174 Hz out, as the guide to chakras and frequencies shows.

Harmonance's own page puts it more quietly, as comfort and grounding: a low, steady tone that works as a kind of floor under a quiet sitting. None of these descriptions comes from a measurement. The number is modern, the anaesthetic label has no test behind it, and the one study that asked people how 174 Hz sounded found it calm, as it found low tones in general.

Where does 174 Hz come from?

174 Hz comes from the modern Solfeggio set, and it joined the set after the first six numbers had been published. The set began with a 1999 book, Healing Codes for the Biological Apocalypse, which drew six numbers from verse numbers in the Bible's Book of Numbers. Its publisher's press release announced them:

the codes revealed a series of six electromagnetic sound frequencies that correspond to the six missing tones of the ancient Solfeggio scale

The six run from 396 to 852 Hz, and 174 is not among them.

Within two years, sets of nine were in use. A tuning fork maker's page, as the Internet Archive saved it in 2012, asks "Why 6 forks when others have gone to 9?" and dates its own debate about going to nine to November 2000. Who first added the three new numbers, 174, 285 and 963, is not recorded.

All nine appear together, with a date, in a US trademark application filed by Leonard Horowitz, one of the book's two authors, in February 2007. It lists them as "396, 417, 528, 639, 741, 852, 963, 174, and 285": the book's six, then 963, then 174 in eighth place.

That order is a count. Write the nine from lowest to highest and each number adds 1 to every digit of the one before, with 9 wrapping round to 1. One step past 963 is therefore 174, and one more is 285. The 963 Hz guide draws the whole count, and the guide to 174, 417 and 741 Hz works through the verse arithmetic behind those three.

The name is much older than the numbers. Its syllables, ut, re, mi, fa, sol and la, come from a medieval hymn, and in medieval teaching they named the six steps of a hexachord: whole tones, with one semitone in the middle. They were steps, not fixed pitches, and "Each hexachord could start on G, C, or F". The strings on the 174 Hz page land on one of those hexachords, as the section on its sound shows.

Why is 174 Hz called a natural anaesthetic?

No early record explains the label. The 1999 press release leaves 174 out, and neither the tuning fork maker's page nor the 2007 filing describes it. The oldest dated copy of the phrase we could find is in a US patent filed in 2016 for a way of processing recorded sound. It lists the nine tones with their notes, "174 Hz = F3" among them, and says:

the lowest of the tones appears to be a natural anesthetic

The same passage credits further work by Leonard Horowitz with having "revealed three more Solfeggio frequencies", but it cites no test of the anaesthetic idea, and the patent is about processing audio, not about what listeners feel. A wider search found no older dated source for the phrase, and nothing that traces it to the book's authors.

The researchers behind a small Japanese pilot that played 174 Hz to people agree. Writing about the anaesthetic idea, they say it "remains largely hypothetical and lacks direct neurophysiological verification", and they leave open "whether this frequency exerts specific analgesic effects beyond general relaxation". We do not repeat the label as a promise. On Harmonance, 174 Hz is a low, steady sound to settle with.

What happened when researchers played 174 Hz to people?

Two studies that played 174 Hz to people could be read in full. Neither tests a benefit, and one of them rests on a single listener. PubMed, the main index of medical research, lists no study of listening to 174 Hz. Three records there mention the tone, each for something else:

a sleep study of 20 students over three nights that used 174 Hz as the carrier of a delta binaural beat, so it tests the beat, not the tone;
a test of a practice called Biofield Tuning, in which three practitioners combed the same 10 volunteers with a 174 Hz tuning fork and matched each other only 33% of the time, which the authors judged poor agreement;
a study of noise on zebrafish embryos, in which 174 Hz "appeared largely benign".

37 adults rating twelve pure tones, Canberra

Researchers at the Australian National University ran an online test in which 37 adults, aged 20 to 55, heard twelve pure tones for 20 seconds each: the nine Solfeggio tones plus 110, 220 and 440 Hz (Kumar, Abhayapala and Samarasinghe, 2022). For each tone they rated, on a scale of 1 to 10, how happy, sad, calm and angry it sounded, comparing it with the tone before and the tone after.

174 Hz was rated the calmest-sounding of the nine Solfeggio tones, at about 8 out of 10, and among the least angry. Only the lowest tone in the test, 110 Hz, which is not a Solfeggio number, sounded calmer. Broadly, the higher the tone, the less calm it sounded, down to about 2 for 963 Hz.

How calm each tone sounded to the 37 Canberra listeners, on average, for the five lowest of the twelve tones and the highest, as read from the paper's graph of average ratings.

Calm ratings, out of 10
Tone	Calm, out of 10
110 Hz, a test tone	8.3
174 Hz, the lowest Solfeggio tone	8.1
220 Hz, a test tone	7.6
285 Hz	6.7
396 Hz	5.0
963 Hz, the highest Solfeggio tone	1.9

The test asked how each tone sounded, not how the listeners felt. The tones always came in rising order and were judged against their neighbours, so the ratings may follow the order as much as the sound. The volunteers used their own headphones at home, and the sample was young, with an average age of 27. What the test does suggest is that many people hear a low pure tone as calmer than a high one, and 174 Hz is the lowest of the nine.

One listener and five minutes of sound, Japan

A small pilot in Japan gave each of five Solfeggio tones, 174, 396, 528, 639 and 963 Hz, to two healthy adults (Wago, Bando and others, 2026). Each heard five minutes of the sound alone and then five minutes of the sound with a colour video, while the researchers recorded brainwaves and heart rhythm, took saliva samples and asked for a relaxation score out of 10. Everyone knew what they were hearing, and there was no comparison group. For 174 Hz, the papers report results for one listener only.

The one 174 Hz listener with results in the Japanese pilot, from the first paper's table: heart rhythm variation and relaxation before and after five minutes of sound alone, then before and after five minutes with the video, and one salivary amylase reading for each part. SDNN measures how much the time between heartbeats varies.

The one 174 Hz listener
Measure	Sound alone	Sound and video
Heart rhythm variation, SDNN	46.7 to 55.8	58.1 to 79.3
Relaxation, out of 10	9 to 10	8 to 10
Salivary amylase	12 KU/L	12 KU/L

The authors read these numbers as a settled response: the heart's rhythm varied more, the relaxation score was high, and amylase, an enzyme in saliva, stayed low, which they take as a sign that the body's stress response was quiet. Their first paper sums the tone up as "A frequency that stabilizes the mind".

Two details make that reading weaker than it sounds. The first paper's text says this listener's alpha brainwaves, which the authors link with relaxation, rose with the sound and rose further with the video, while its own table shows eyes-closed alpha falling with the video, from 19.1 to 3.8. With the text and the table at odds, we give no alpha figure. The two papers' tables also disagree on the relaxation scores: the first has 9 rising to 10 and 8 rising to 10, while the second lists 9 and 8.

Even taken at face value, one person cannot show what a tone does. The same group's later paper says so plainly: 174 Hz was "unassessable for this study", because "Our clinical experience included actually one case". The group is open about its limits in general: the number of people is "small and insufficient for statistical verification", and the influence of expectation "cannot be completely excluded".

What the studies add up to

Neither study shows a benefit of 174 Hz, or any harm. The rating test found it calm-sounding, as it found low tones in general, and the pilot's one listener scored relaxation high, in figures its papers do not report consistently. Both are small, and the wider field is not much further along. The US National Center for Complementary and Integrative Health sums up music research in general:

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

For listening, the useful part is simple. If you want a tone that most people hear as calm, a low one is the likelier choice, and 174 Hz is the lowest of the nine. Whether it does anything more than sound calm, nobody has shown. Play it softly for a few minutes and notice whether it settles you. If the low hum feels heavy, its neighbour in the set, 285 Hz, sits higher and lighter.

What does 174 Hz sound like?

174 Hz is a low, warm tone. On a piano tuned to A at 440 Hz it sits a shade under F3, the F below middle C: 6 cents under the F at 174.61 Hz, where a cent is a hundredth of a semitone. Halve it and you reach its lower octave, 87 Hz; double it and you reach 348 and then 696 Hz, the same note higher up. In air at room temperature its wavelength is nearly 2 metres.

The 174 Hz page plays it in two ways, and we measured both from the page's own audio files.

Paired bars by octave band: the tone alone puts 99.4% of its energy around 174 Hz; with Strings, half of it lies an octave higher — With Strings off, the 174 Hz page puts 99.4% of its sound in the band around 174 Hz; with Strings on, half of it, 49.5%, lies an octave higher, around 348 Hz, and the 174 Hz tone plays 35.8 dB under the music.

The numbers behind the chart
Octave band	Tone alone	Strings
1,392 Hz, three octaves up	0%	1.3%
696 Hz, two octaves up	0%	10.9%
348 Hz, one octave up	0.5%	49.5%
174 Hz, the tone itself	99.4%	30.8%
87 Hz, one octave down	0%	7.4%

Download the measurements (CSV)

With Strings off, the page plays the tone on its own. It is not a perfectly pure sine: two faint overtones sit above it, at 348 Hz, 23.1 dB quieter, and at 522 Hz, 34 dB quieter.

With Strings on, the weight moves up. The strings play slow chords around the tone, and their strongest line is its octave, at 348 Hz. The exact 174 Hz tone still plays underneath, far below the music.

Which notes do the strings play? Their eight strongest lines fall on just six notes, and those six are not a random handful.

A piano keyboard with 174 Hz marked just under F3 and the strings' eight strongest notes lit, above bars for the six notes F, G, A, B flat, C and D — On the keyboard, 174 Hz sits 6 cents under F3. Gathered into one octave, the strings' sound falls on six notes, F, G, A, B flat, C and D, which together hold 95.2% of its energy.

Six notes a whole tone apart, except for the semitone between A and B flat, make a hexachord: the six steps of the medieval syllables, ut, re, mi, fa, sol and la, here starting on F. The strings play one Harmonance score on every page, pitched so that its home note falls on the page's tone, and that score keeps mostly to six notes. The hexachord is the score's own shape, not something chosen for 174 Hz. On 174 Hz it happens to start on F, one of the three notes a medieval hexachord could start on, where fa falls on B flat.

Played at the same level, 174 Hz also sounds quieter than higher tones: hearing is most sensitive between 2 and 5 kHz, and grows less sensitive the lower a tone sits.

How long should you listen to 174 Hz, and how loud?

No study sets a length for 174 Hz: the pilot played it for five minutes and the rating test for 20 seconds. Harmonance's page suggests fifteen to thirty minutes at a low volume, through a speaker rather than tight in-ear buds, and stepping away if the low hum ever feels heavy rather than restful.

Keep the volume low, even though a low tone tempts you to turn it up. Loud listening is the one risk that is well established. The US National Center for Complementary and Integrative Health notes that "listening to music at too high a volume can contribute to noise-induced hearing loss", and the World Health Organization's safe listening advice is that "you can safely listen to a sound level of 80dB for up to 40 hours a week", with your device's volume at no more than 60% of maximum.

How do you listen to 174 Hz on Harmonance?

Press play on the 174 Hz page. With Strings off it plays the tone alone; switch Strings on beside the player and the strings carry the same note across its octaves. Nothing plays until you press play, and no account is needed.

In Harmonance Studio you can set 174 Hz under other tones and shape your own mix. Its nearest neighbour in the set is 285 Hz, and the Solfeggio collection plays all nine.

The grounded page, for when you want to feel grounded, sets 174 Hz beside 396 Hz and Saturn's tone. For the wider field, what the science of sound healing shows sets out what research on sound and music has and has not found, and the guide to the Solfeggio frequencies follows the whole set, tone by tone.

Sources and limits

The history of the number rests on the 1999 press release, a tuning fork maker's page, a US trademark record and a US patent, each read in its original or archived form. The research is two small studies: an online rating test of pure tones, and a pilot whose 174 Hz results come from one listener, in figures its papers do not report consistently. Neither can say what 174 Hz does for anyone. The three PubMed records mention 174 Hz without testing it. The calm ratings were read from the Canberra paper's graph, so each is good to about a tenth. The measurements of the 174 Hz page are Harmonance's own, made from the page's audio files.