Blog » Myth ⚠ The Ancient Solfeggio Tone Frequencies

Reading Time: 22 minutesOctober 2, 2013

if you ended up here at this article because of Dr. Horowitz’ critics (at about my article (written on the 2nd of October 2013) and me in person, then you might like to read my thoughts about what he wrote.

I suggest though that you read this article below (from top to bottom) first before you do.



In various online sources, a series of frequencies are listed as “The Ancient Solfeggio Frequencies” as been revealed by Dr. Joseph Puleo and Leonard G. Horowitz.

The proclaimed “Solfeggio frequencies” are:

    • UT – 396 Hz – Liberating Guilt and Fear
    • RE – 417 Hz – Undoing Situations and Facilitating Change
    • MI – 528 Hz – Transformation and Miracles (DNA Repair)
    • FA – 639 Hz – Connecting/Relationships
    • SOL – 741 Hz – Awakening Intuition
    • LA – 852 Hz – Returning to Spiritual Order

In Dr. Horowitz’s concept 3 more frequencies are listed (963, 174 and 285, totaling 9 frequencies), but since only those 6 above have “sol-fa syllables” it seems logical to look at those primarily, to find out of the proclaimed relationship with solmization (and thus the “Solfeggio Tones) and the proclaimed frequencies do actually exist.


Let’s have a look in the dictionary. Since this note is written in English, I will refer to what is written in English / American dictionaries. 

solfeggio (The American Heritage Dictionary of the English Language)

sol·feg·gio  (sl-fj-, -fj)·feg·gi (-fj) or sol·feg·giosMusic

1. Use of the sol-fa syllables to note the tones of the scale; solmization.

2. A singing exercise in which the sol-fa syllables are used instead :of text.

[Italian, from solfa, sol-fa; see sol-fa.]

solfeggio (Collins English Dictionary – Complete and Unabridged)

solfeggio [sɒlˈfɛdʒɪəʊ], solfège [sɒlˈfɛʒ]

n pl -feggi [-ˈfɛdʒiː] -feggios-fèges Music

1. (Music, other) a voice exercise in which runs, scales, etc., are sung to the same syllable or syllables

2. (Music, other) solmization, esp the French or Italian system, in which the names correspond to the notes of the scale of C major

[from Italian solfeggiare to use the syllables sol-fa; see gamut]

gamut (Collins English Dictionary – Complete and Unabridged)

gamut [ˈgæmət]


1. entire range or scale, as of emotions

2. (Music / Classical Music) Music

a.  a scale, esp (in medieval theory) one starting on the G on the bottom line of the bass staff

b.  the whole range of notes

3. (Physics / General Physics) Physics the range of chromaticities that can be obtained by mixing three colours

[from Medieval Latin, changed from gamma ut, from gamma, the lowest note of the hexachord as established by Guido d’Arezzo + ut (now, doh), the first of the notes of the scale ut, re, mi, fa, sol, la, si, derived from a Latin hymn to St John: Ut queant laxis resonare fibris, Mira gestorum famuli tuorum, Solve polluti labi reatum, Sancte Iohannes]

NOTE: If you come across definitions of Solfeggio in other official dictionaries in other languages that do not match these below, then please do let me know, so I can update this article. Thanks!


In music, solfège (French pronunciation: [sɔl.fɛʒ], also called solfeggiosol-fasolfedge, or solfa) is a pedagogical solmization technique for the teaching of sight-singing in which each note of the score is sung to a special syllable, called a solfège syllable (or “sol-fa syllable”). The seven syllables commonly used for this practice in English-speaking countries are: do (or doh in tonic sol-fa), remifasol (so intonic sol-fa), la, and ti/si 

 (Source: Wikipedia)

It’s Origin:

The use of a seven-note diatonic musical scale is “ancient”, though originally it was played in descending order.In the eleventh century, the music theorist Guido d’Arezzo developed a six-note ascending scale that went as follows: Ut, Re, Mi, Fa, Sol, and La.

The names were taken from the first verse of the Latin hymn Ut queant laxis, where the syllables fall on their corresponding scale degree (except for  “si”).

“Ut” was changed in 1600 in Italy to the open syllable Do, at the suggestion of the musicologue Giovanni Battista Doni, and Si (from the initials for “Sancte Iohannes”) was added to complete the diatonic scale. In Anglo-Saxon countries, “si” was changed to “ti” by Sarah Glover in the nineteenth century so that every syllable might begin with a different letter. 

In the Elizabethan era, England and its related territories used only four of the syllables: mi, fa, sol, and la. “Mi” stood for modern ti, “fa” for modern do or ut, “sol” for modern re, and “la” for modern mi. Then, fa, sol and la would be repeated to also stand for their modern counterparts, resulting in the scale being fa, sol, la, fa, sol, la, mi, fa. This was eventually eliminated by the 19th century, but it was (and still is in a few rare circumstances) used in the shape note system, which gives each solfège syllable a different shape.

(Source: Wikipedia)

Wikipedia also mentiones:

There are two main types of solfège:

  1. Movable do, or solfa, in which each syllable corresponds to a scale degree. This is analogous to the Guidonian practice of giving each degree of the hexachord a solfège name, and is mostly used in Germanic countries.
  2. Fixed do, in which each syllable corresponds to the name of a note. This is analogous to the Romance system naming pitches after the solfège syllables, and is used in Romance and Slavic countries, among others.

(Source: Wikipedia)

NOTEThere are various alternatives mentioned on Wikipedia about the possible origin of the Solfeggio Syllables. BUT, since Dr. Joseph Puleo and Leonard G. Horowitz refer to Guido d’Arezzo in their “Ancient Solfeggio Frequencies” theory, I will do so too, in order to “test” the proclaimed “relationship” between the frequencies and syllables. 


In the online sources about “The Ancient Solfeggio Frequencies” there is a passage about “hidden entries from Webster’s Dictionary and the Original Greek Apocrypha” that provided “definitions of each of the original syllables“. 

Precise references and background information about these “hidden entries” and related “definitions” are not mentioned, and can there for not be confirmed or proven as their proclaimed “functions” or unique “qualities”. I do hope I will find more information about this subject, it is an intriguing topic.

So, what can we say about the Solfeggio Syllables? 

There are two solfège systems (Source: Wikipedia)

1. The “Fixed Do” system: links the syllables to a specific tone, where “Do” represents “C”. 

“Fixed Do” Solfeggio Syllable tone connection:

  • C = (Ut / Do)
  • D = (Re)
  • E = (Mi)
  • F = (Fa)
  • G = (Sol)
  • A = (La)
  • B = (Si / Ti)

! ! ! According to Horowitz C5 = 528Hz. Horowitz also lists Mi = 528Hz. In the “Fixed Do” system Mi = E, NOT C. So, what to think of that? You can’t have both C and E at 528Hz.

2. The “Movable Do” system: does not link the syllables to a specific tone (or frequency), but to the relationship between (the position of) the tones in the scale. The “Do” is always the tonic, the first degree of the scale. If – for example – a composition is written in G Major, then the tone “G” would be the first degree and there for the “Do”. This “Movable Do” system, was the system that Guido d’Arezzo is said to have used.

“Movable Do” Solfeggio Syllable degree connection:

  • UT / DO = Tonic
  • RE = Supertonic
  • MI = Mediant
  • FA = Subdominant
  • SOL = Dominant
  • LA = Submediant
  • SI / TI = Leading Tone
  • UT / DO = Octave (Tonic)

IF Guido d’Arezzo used the ‘movable Do’ system, then we may conclude that relating specific ‘tone names’ (C, D, E, et cetera) and/or ‘tone pitches’ (frequencies) to the Solfeggio Syllables is not logical (or even possible). Any tone could be a “Do” (as long as that tone would be the tonic of the tonality) and the particular frequency of that “Do” would furthermore depend on Concert Pitch and Temperament as well.


In the table below I only show 6 of the 9 frequencies provided by Dr. Horowitz. The reason for this is that only 6 of the proclaimed frequencies are paired with one of the 6 initial (original) Sol-fa Syllables. Even if we would at the much later added “SI” or “TI” then there would be still 2 frequencies without syllable.

As mentioned earlier, according to Horowitz C5 = 528Hz. Horowitz also lists Mi = 528Hz. In the “Fixed Do” system Mi = E, NOT C. You can’t have both C and E at 528Hz with the “Fixed Do” system. So, we have to chose … 

If the “fixed Do” system was used, then we may assume that “Ut” (or “Do”) relates (according to Dr. Puleo and Leonard Horowitz) to the tone “C”, and because they list UT at 396Hz we will presumed C=396Hz, not 528Hz, as it is listed as “Mi”. In comparison with the 12-TET scale under concert pitch A4=440Hz, there are some major differences.

In the table below I start with UT or C at 396Hz as suggested by Michael Walton and later published by Dr. Horowitz.



396Hz 523.251Hz (C5) 482.40328002554713 5


417Hz 587.330Hz (D5) 592.9487362857523 6


528Hz 659.255Hz (E5) 384.3584140878282 4


639Hz 698.456Hz (F5)  154.0239638067158 1.5


741Hz 783.991Hz (G5)  97.63626019691937 1


852Hz 880.000Hz (A5) 55.9801119585857  0.5

Could there be a logical reason for these tones to differ so much? 

The answer is YES, the frequency of a tone is related to the used concert pitch and temperament. For those who are not familiar with the terms, more information about these terms can be found here: Concert Pitch & Temperament.

From what we have read so far, we could conclude that Guido d’Arezzo (991/992 – 1050) worked on his Solfeggio system in a period when there was no standard concert pitch. In the past a variety of concert pitches have been used for A4, from 360 Hz (in England) up to 460 Hz (in Germany). 

According to Dr. Puleo and Leonard Horowitz “LA” (A) should be 852Hz. At present time A5=880Hz. This is a difference of 55.9801119585857 cents, that is only little more then a quarter-tone. The concert pitch A4 would then be around 426Hz (depending on the temperament used), a concert pitch that could have been used in the past. 

With concert pitch alone we’re not there yet. Especially if you keep in mind that the temperament used nowadays (12-TET – 12 Tone Equal Temperament), has not always been the standard.

Earlier I mentioned that Guido d’Arezzo developed his Solfeggio system in between 991/992 (birth) and 1050 (death). It was not until around 1400 that the Pythagorean temperament was replaced with the “Meantone Temperament”. There for we may assume that in the time of Guido d’Arezzo the Pythagorean temperament (Circle of Perfect Fifths – CoPF) was used. 

Now, let’s take the “Ancient Solfeggio Frequencies” and “line them up” the way they would, as if the Pythagorean temperament was used. Since ‘UT” is proclaimed to be 396Hz, we will start calculating the Circle of Fifths from the same frequency, so we can compare the result of going ’round the circle using perfect fifths. A perfect fifth = 701.96 cents. Note: the CoF frequencies are rounded up to the nearest whole number in this example.

 SYS. UT (C) SOL (G) RE (D) LA (A)  MI (E)  FA (F) 
HOR. 396Hz 741Hz 417Hz 852Hz 528Hz 639Hz
CoF 396Hz 594Hz 891Hz 1337Hz 2005Hz 34254Hz

The frequency outcome obove ranges over multiple octaves. The “Solfeggio Frequencies” are spread over two octaves (the frequencies of Ut (C) and Re (D) are located in the so called “1-line Octave” the other tones in the “2-line Octave”). The freqiencies of the CoF as listed above cover approx. 7 octaves.

In order for us to compare these frequencies, we have to bring some down a couple octaves in between C4=396Hz – C5=792Hz. Now, let’s compare these frequencies:  

 SYS. UT (C) RE (D) MI (E)  FA (F) SOL (G) LA (A)
HOR. 396Hz 417Hz 528Hz 639Hz 741Hz 426Hz
CoF 396Hz 446Hz 501Hz 535Hz 594Hz 668Hz

From the information above, we may conclude that the Pythagorean temperament can be “ruled out” as temperament for the “Ancient Solfeggio Frequencies”, as well as any temperament that came after. Pythagoras supposed to have lived between approx. 495 – 570 BC.

It is almost certain that Paolo Diacono wrote his composition using the local musical “traditions” of that time, which would mean the Pythagorean temperament.

This means that IF Italian Benedictine monk and music theorist Guido d’Arezzo used a different temperament then Pythagorean, this must have been older then the Pythagorean temperament, or must have been “imported” from another region then the South of Europe. Horowitz does not provide any evidence what’s however though that this is the case. Zero proof!

Why would Guido d’Arezzo chose to use the ‘Ut queant laxis’ hyme for his syllables, if the actual tones / frequencies of that piece would not ‘match’ the tones frequencies as proclaimed by Horowitz? That would be rather strange, wouldn’t it? It just does not make sense to “link” the Horowitz numbers to those syllables.


AN · CIENT (ān′shənt)


1. Of, relating to, or belonging to times long past, especially before the fall of the Western Roman Empire
(ad 476): ancient cultures.
2. Of great age; very old.
3. Archaic Having the qualities associated with age, wisdom, or long use; venerable.


Ancient history is the aggregate of past events from the beginning of recorded human history and extending as far as the Early Middle Ages or the Postclassical Era

Although the ending date of ancient history is disputed, some Western scholars use the fall of the Western Roman Empire in 476 AD (the most used), the closure of the Platonic Academy in 529 AD, the death of the emperor Justinian I in 565 ADthe coming of Islam (early-7th century) or the rise of Charlemagne (740-814 AD) as the end of ancient and Classical European history.


Let’s place the by Puleo/Horowitz proclaimed sources in historical perspective:


The Latin hymn “Ut queant laxis” – written by the Italian Benedictine monk Paolo Diacono (c. 720s – probably 799 AD) – was used as foundation for the creation of the Solfeggio Syllables. This places this Latin hymn in the Middle Ages, at best at the very end of the Ancient and European Classic Antiquity (not to be mistaken for the Classic Period in Music), the Late Antiquity (4th to 7th centuries AD).


Guido d’Arezzo (991/992 – after 1033 AD) was an Italian music theorist of the “Post-Classical” history (that immediately followed ancient history). If Guido of d’Arezzo is the creator of the Solfeggio system – as proclaimed by Puleo/Horowitz as well (as the contributors of Wikipedia and most historical lecture on this subject) – then we can place Guido d’Arezzo in a time frame AFTER the Late Antiquity (4th to 7th centuries AD).

WITH OTHER WORDS: The Solfeggio System is thus not an invention from “ancient” times, but that of the “Post-Classical” period.  using the term “Ancient” in relationship with “Solfeggio” is historically inaccurate, suggestive or perhaps “misleading” is a better word to describe it.



We have looked at the term “Solfeggio” from a musicological point of view and we have “done the math” when it comes to temperaments and tuning, but none of it “matches”

We have looked at the historical timeline to find out if the sources and the proclaimed “ancientness” align, and yet again, no proper match!

Could this mean that Horowitz simply “borrowed” a musical term and “glued” it onto “his own” (although Marko Rodin might disagree about that) number-concept?

Did Horowitz simply “gathered” different pieces of information, put in a blender, wrap it in a self-fabricated story and then “sell” it to the world as the “Ancient Solfeggio Tones”?


For centuries it was thought that sound was so ephemeral that any attempt to capture it — to hold a ruler against it — would be a fruitless exercise. In fact, until the 17th century natural philosophers thought it absolutely illogical to make any attempt to quantify it or even theorize about its measurement.

One of the first discoveries regarding sound was made in the sixth century B.C. by the Greek mathematician and philosopher Pythagoras. He noted the relationship between the length of a vibrating string and the tone it produces. 

The possibility that sound exhibits analogous behavior was emphasized by historical figures such as the Greek philosopher Chrysippus (c. 240 B.C.), by the Roman architect and engineer Vetruvius (c. 25 B.C.), and by the Roman philosopher Boethius (A.D. 480-524). The wave interpretation was also consistent with Aristotle‘s (384-322 B.C.) statement to the effect that air motion is generated by a source, “thrusting forward in like manner the adjoining air, to that the sound travels unaltered in quality as far as the disturbance of the air manages to reach.” Also Leonardo da Vinci came around 1500 to the conclusion that sound “travels”.

It wasn’t until 1638 when Galileo came with an explanation of the relation of pitch to frequency, consonance, and dissonance. The mathematical theory of sound propagation began with Isaac Newton (1642-1727), whose Principia (1686) included a mechanical interpretation of sound as being “pressure” pulses transmitted through neighboring fluid particles.

In March 1676 the great British scientist Robert Hooke (1635-1703) described in his diary a sound-producing machine. Hooke noted a regular pattern of teeth produced music-like sounds, while more irregular teeth (on a wheel) produced something that sounded more like speech.

By 1834 the Frenchman Félix Savart (1791-1841) was building giant brass wheels 82cm across, with 720 teeth. Savart’s contribution was a mechanical tachometer connected to the axis of the toothed wheel. He calibrated a rotational scale with the tooth rate, and for the first time demonstrated that specific tones were associated with specific frequencies. He could determine the frequency of a tone heard in air by using his ear to match it with the toothed wheel and reading the frequency from the tachometer. He was using his ear and brain to do what a modern electrical engineer would call heterodyne analysis.

John Shore‘s* (1662-1752) contribution to the science of measurement was the invention* of the tuning fork — a frequency standard that was now available an that we can still refer to. According to the “432 Octaves” website it wasn’t John Shore who invented the tuning fork, but the Egyptians, but I have not seen sufficient evidence to confirm or deny this.

It wasn’t up to the “Electrical Era” when scientists could start measuring sound frequency more accurate, using a combination of tools, such as the Microphone (the carbon- button microphone invented by Thomas Edison and Emile Berliner simultaneously in 1876), the Galvanometer (to measure the tiny electrical currents inside the human body invented by Jacques-Arsène d’Arsonval in 1882), the Thermophone and a vacuum tube to amplify the output of the measurement microphone. These inventions made it possible – when combined – to measure sound frequencies accurately. 

Side note: If you like to know more about how to use microphones, then perhaps you like to read: “3 Main Types Of Microphones Explained” by Jeremy Bongiorno.

What I like to make clear with this short historical “time-line”, is that in the time of Guido d’Arezzo no measurement tools exist, nor where philosophers and “scientists” much aware of the exact pitch (frequency) of tones. Guido d’Arezzo could not have know the frequencies represented by his “Do-Re-Mi”. It wasn’t until the “Electrical Era” when accurate measurements could be done regarding frequencies.

Thus, “linking” specific frequencies to the “Do-Re-Mi” is from an historical and scientific point of view pure speculation.


According to Horowitz mankind started to get “out of sync” with the natural world after the world adopted a standardized tuning frequency of A4=440Hz.


More harmonious alternatives have been obviously suppressed. For instance, during the past decade, A=444Hz (C5=528Hz) analysis found this frequency more compatible with nature.

Two notes in any just (pure) interval are members of the same harmonic series. Pure intervals are important in music because they naturally tend to be perceived by humans as “consonant“, with other words pleasing and HARMONIOUS. You can’t get more “natural”, more “harmonious” when it comes to musical tuning then when you use Just intervals.

This said, let’s have a look at some of the proclaimed frequencies:

The frequency C=528Hz is a Just minor third (ratio 6:5) above 440Hz. Both tones also match harmoniously with G=396Hz with ratio 4:3=528Hz (Perfect “Just” Fourth) and ratio 10:9=440Hz (Just Major second). 444Hz would in fact be LESS in tune with “nature” (LESS HARMONIC) in relationship with 528Hz, 444Hz requires C=532,8Hz, almost 5Hz too high to be “Just”.


Not coincidently metaphysically, the interval between A=440Hz (equivalent to F#=741Hz in the ancient original Solfeggio scale) and A=444Hz (C5=528Hz in the ancient original Solfeggio scale) is classically known as the Devil’s Interval in musicology, due to its highly aversive disharmonious sound made when these two notes are played simultaneously.

440Hz metaphysically the equivalent to 741Hz? That sounds rather fancy, but what is he actually saying? What he seems to be saying is: “440Hz is in a theoretical, esoteric and hard to understand manner equal in value to 741Hz“. How does he figure that?!

Let’s take a look at this claim from a musicological standpoint:

440Hz and 741Hz are approx. 9 semitones (a Major sixth) apart. To be precise, F# (in 12-TET at Concert Pitch C4=440Hz +900 cents) would be 740Hz (739.989) and the Pythagorean Major sixth (ratio 27:16, 906 cents) would be 742.5Hz. The tones 440Hz and 741Hz are obviously different tones, these tones are not each others “equivalent”, nor inversion, nor do they mathematically have anything in common. Even when you count up their numbers (something Horowitz likes to use as validation for his theory) values are different: 4+4+0=8, 7+4+1=12=3.

Let’s take another look at Horowitz’ claim, stripping it from it’s “clutter”:

Not coincidently metaphysically, the interval between A=440Hz (equivalent to F#=741Hz in the ancient original Solfeggio scale) and A=444Hz (C5=528Hz in the ancient original Solfeggio scale) is classically known as the Devil’s Interval in musicology 

Oh, really? The “Devil’s Interval” or better known among musicologists, musicians, composers and sound engineers as a “Tritone“, is the interval between two tones that are 6 semitones (approx. 600 cents – depending on the temperament) apart. The difference between A4=440Hz and A4=444Hz of approx. 47.43 cents is (as mentioned earlier in this article) actually an interval called “Greater 37-limit quarter tone” and is used in temperaments such as 47-Limit and 311-EDO.

It might also be good to mention that the Tritone is commonly used in modern music. Take for example the commonly used Dominant 7 chord of C. It contains the following tones: C-E-G-Bb. The distance between the 3rd (E) and 7th (Bb) is a Tritone. The Tritone or “Devil’s Interval” is nothing “spooky” or “mysterious” thus, and has nothing to do with the difference between 440Hz and 444Hz.


One of the most absurd claims Horowitz made is about the Rockefeller-Rothschild and Nazi Germany “connection” in relationship with the introduction of 440Hz as Concert Pitch:

Ironically, and most revealing about the Anglo-American cartel arrangement, to persuade European musicians to accept this tuning, and the British Standards Institute (BSI) adoption of it in 1939, Rockefeller-Rothschild “black-op” officials employed Nazi party propagandist, Joseph Goebbels.

Lynn Cavanagh reviewed the history of standard musical tuning and determined that contrary to propaganda, and current consensus, it was 1939, not 1938, as the true year the British Standards Institute (BSI) adopted the A=440Hz standard promoted by the Rockefeller-Nazi consortium.

You can read more about this fable in the article: “The Goebbels Concert Pitch Story” at Roel’s World.


This knowledge best explains why so many musicians intuitively feel better tuning up, or down, a bit sharp or flat, from A=440Hz “standard tuning.

I am pretty sure the misinterpretations, misinformation and “hocus-pocus” with musical terms and numbers in Horowitz’ “Ancient Solfeggio Tones” concept can not be labeled as “knowledge”. Words that do seem to fit Horowitz’ claims better are probably: “fiction”, “ineptness”, “incompetence”, “ignorance” … No real musician (or for that matter composer, musicologist, producer or sound engineer) would ever use those claims to validate this flawed concept.


Because the Ancient solfeggio Frequencies concept by Horowitz included A4=444Hz, it is good to check that out as well. The difference between 444Hz and 432Hz is 47.434037023964734 cents. This interval (47.43 cents) with ratio 37:36 and Prime Factors 37:22·32 is actually an interval called “Greater 37-limit quarter tone” and is used in temperaments such as 47-Limit and 311-EDO. This though, has nothing to do with the “Ancient Solfeggio Frequencies” concept by Horowitz and Puleo, nor with the 432-Tuning concept.

In some online articles you can find information about the “Ancient Solfeggio Frequencies” and “432-Tuning” all mixed-up together, as if it is the same concept. Those who have spend a bit more time reading into all of this, should have noticed that Horowitz sets A4 to 444Hz, NOT 432Hz. Of course it is possible to create a “temperament” where you could add both frequencies, but there isn’t a single tuning system where multiple frequencies are used for a single tone. A4 can not be both 444Hz and 432Hz at the same time. That by itself should be enough “evidence” to point out that we are talking about two different 12-Tone tuning systems.

SCALES WITH BOTH 432Hz and 528Hz

Arithmetically (number theory) 528 is an abundant number (or “excessive” number), because the sum of its proper divisors (960) is greater than itself. Its abundance is 432.

The difference between 432Hz and 528Hz is 347.40794063398204 cents. That is 3 semitones (3×100 cents) plus 47.40794063398204 cents. The interval of 347.41 cents (ratio 11:9 and Prime Factors 11:32) is called the “Undecimal Neutral Third.”

Bo Constantinsen created a tuning concept called “The Sacred Sound Scale” that places 424Hz (Ra-Tuning), 432Hz, 440Hz and 444Hz (& 528Hz) (Horowitz) within one tuning concept. The scale has 32+1 pure harmonic tones and the reference frequency of 256 Hz (Scientific Pitch). It comes from the Natural Ascending Series of Harmonics 32 to 64 of the 8 Hz Fundamental Tone, and represents its 6th double.

In recent years Robert E Grant explored and shared the direct relationships between mathematics, geometry, cosmology and music, something I have been blogging as well since 2013 on Roel’s World. In June 25, 2021 Robert published an article about his Precise Temperament Tuning. It’s an interesting concept, I wrote an article about it.


Horowitz hasn’t been the only one labeling a particular series of numbers with the term “Solfeggio”. After his wake of publications various others have been “building upon it”, some probably unaware they are using a “borrowed” and unrelated musical term (referring to “Solmization”) for their work (often not at all related to music theory at all!).

Take for example the various “Solfeggio Magic Squares” and tables you can find online:

Now, to make this absolutely clear:

I don’t say their math is wrong, or that these numbers, these “magic squares” are of no value or so. On the contrary. I’m just saying that by calling them “Solfeggio” you create more confusion then clarity by using that musical term. 

SO, WHAT ABOUT 396Hz, 417Hz, 528Hz, 639Hz, 741Hz & 852Hz?

In various online sources about the “Ancient Solfeggio Frequencies”, the following passage can be found:

“As we look at the six original Solfeggio frequencies, using the Pythagorean method, we find the base or root vibrational numbers are 3, 6, & 9. Nicola Tesla tells us, and I quote: “If you only knew the magnificence of the 3, 6 and 9, then you would have a key to the universe.” ~ L. Horowitz.

That source mentions the use of Pythagorean method (I presume the summing of digits to get to the “digital root” of a number). When we do so with the list of frequencies, we indeed get the numbers 3, 6 and 9. Well, many other number could lead back to 3, 6, or 9 … for example 111 (=3), or 411 (=6), 12321 (=9), et cetera. That fact alone does not tell us those numbers are important sound frequencies, now does it?  

Then, about the Nicola Tesla reference, – as far as we know – Tesla referred to electromagnetic radiation, NOT sound. I have not been able to find any sources stating Nicola Tesla being an acoustician or sound/tone engineer, or even an “amature musician”, nor is it clear if – when making his statement – he mend sound, instead of electro-magnetic radiation. Electromagnetic waves and Sound waves are not “the same thing”. Their vibratory nature (specially not in the physical world) can not be “exchanged” one-on-one. 

That we use the same word (Hertz) to define the number of cycles per second of a periodic phenomenon, does not mean all phenomenon measured in Hertz, have a direct 1 on 1 relationship. Not only for sound we use the term hertz, but for light (electromagnetic radiation) and radio frequency radiation as well, and even in computing we use the term Hertz for the CPU clock rate.

Guillermo ( made a short video called “Busting the Solfeggio Frequencies Myth” (youtube below) about his search for “pure tones” and his view on the “Solfeggio Frequencies”. He stated:

The numbers used for the “Solfeggio Frequencies” … have their place in sacred geometry, or in numerology, but no greater significance when used as a tone measured in Hertz. … Numbers themselves without the units are symbols. … Sound are not “symbols” but manifestations of the vibratory nature of the physical world. … The mistake made here, is one of mixing the archetypal representations with the human conventions.

UPDATE: not long after Dr. Horowitz’ article “ROEL’S WORLD IS OUT TO LUNCH, OBSESSED TO DISCREDIT 528” (mentioned at the beginning of this blog article) was published this Youtube video created by Guillermo disappeared. 


The frequencies proclaimed by Dr. Joseph Puleo and Leonard G. Horowitz, are misinterpreted “variations” on Marko Rodin Family Number Groups of 1,7,4 and 2,8,5 and 3,9,6. These Family Numbers Groups are nodes (not notes as in written tones) of how energy travels, and not actual (sound) frequencies themselves.

More about Marko Rodin’s work:


Many people wish to believe that when a story “pops-up” over and over again that it must be true. “Where smoke is, there ‘s fire” is often thought. Why would otherwise so many people write about it and support it? Well, it’s hard to see what’s going on when smoke gets in your eyes, perhaps there is too much smoke and not enough fire. Ever thought of that?

Most of the sites that support the “Ancient Solfeggio Frequencies” concept actually just “recycle” the same story with the same data, their sources – if provided – all lead back to Horowitz, not to any other proper historically supported data. Just compare the information and “trace back” their sources …,,,,,,,, … to name a few.

Just google on “Solfeggio” and you’ll find many more …

What is interesting is that pretty much all sites that support this concept are “New-Age” sites and sites by “conspiracy thinkers” (440Hz Goebbels Myth), hardly any serious (top-level) musicians, composers and sound engineers of any (but the New Age) genres support this concept.

On the other “side” there are only a few people besides myself that have questioned the “Ancient Solfeggio Frequencies” concept. Besides Guillermo mentioned in this article there are only a few who question / oppose the Horowitz concept like:, Richard Dobson and Derek Gedney.

Most of the blog articles about the “Ancient Solfeggio Frequencies” seem to have been written by people with good intentions (I presume), but hardly ever with proper music-theoretical and historical knowledge. Most of those sites/blogs provide info and tools/applications for free, but there are also sites/companies that use this concept to sell their products.

Now, you are free to believe what ever you wish to believe, but perhaps you might like to ‘dig’ a bit deeper and “make up your own mind” before you spend your money. Your choice!

  • Wrong usage of term “Solfeggio” – a complete mismatch between Horowitz’ concept and actual music history and theory.
  • The proclaimed meaning of the syllables can not be confirmed, Horowitz does not provide any proper evidence to support his own claim.
  • Wrong usage of term “Ancient” – The proclaimed sources do not match the time frame to be called Ancient. Why creating the appearance something is older then it actually is?
  • The proclaimed frequencies do not match any temperament, not even known temperaments of “Ancient” times. If Horowitz / Puleo had really discovered an unknown ancient temperament, then why did they not provide any proper evidence to support their claim?
  • These frequencies could not have been know to Guido d’Arezzo when he created Solfeggio didactic system, the tools to measure and analyze frequency did not exist yet.
  • Horowitz contradicts himself several times, in particular with his usage of musicological terms, like for example the “Devil’s Interval” (Tritone). It is clear he does not have a proper understanding of music theory. Most obvious is his claim to use C5 = 528Hz that contradicts another claim his own frequency-syllable lists Mi = 528Hz. C is after all “Ut” (Do) according to the Fixed-Do System, not “Mi” (the tone E).
  • Horowitz/Puleo did not ‘discover’ these numbers himself. The ‘front-runner’ in the last couple of decades concerning the numbers mentioned in Horowitz’ concept is Marko Rodin (family number groups) related to Vortex Mathematics.

Musicologically, mathematically and historically the ‘Ancient Solfeggio Frequencies’ 9-tone tuning concept is nothing more then a myth, a figment of Horowitz’ and Puleo’s imagination.

So sharing his flawed pseudo-scientific, pseudo-historical and pseudo-musicological concept as the ‘truth’ might not be in your own best interest. That is, if you like to been taken serious about your music and perhaps your good name and reputation as musician / composer / producer / sound engineer, in my opinion of course.

Do keep in mind though, when you criticize Horowitz’ concept in public you might be “badmouthed” by Horowitz. He tends to play’s the man, not “the ball”, when his believes are criticized.


What ever these numbers are, they are not the o called “Ancient Solfeggio Frequencies”! Perhaps the most logical way to name those numbers is the “Rodin Family Number Groups”.


IMPORTANT: I do NOT proclaim that numbers such as 528 are without meaning, importance or value, perhaps even as tone frequencies for some people. BUT, I personally do not see how the “Ancient Solfeggio Frequencies” (as Puleo/Horowitz like to call them and explained their concept) could ever work in harmony within a proper 12-Tone musical interval system / temperament.

Of course we musicians and composers are free to experiment with any kind of tuning system, as what Bo Constantinsen did with his ‘Sacred Sound Scale’, mentioned earlier in this article. As member of the Xenharmonic community I have seen and heard wilder and more extravagant temperaments then the proclaimed “Solfeggio Frequencies”.

If the frequencies provided by Horowitz sound well to your ears, then by all means, enjoy working with them. Just don’t use or “cycle” his “silly” argumentation (flawed evidence / untruths) to explain why you like to use his concept, you might ‘fool’ people without propper musical education with it, but it makes you look rather “foolish” in the eyes of those who do really understand.

You won’t see / hear me using their concept, the combination of frequencies provided by Horowitz simply does not sound harmonious to my ears.


at about this article (and me in person):

I had almost given up hope, but it turned out to be matter of time only before Dr. Horowitz finally discovered this article (that I wrote on October 2nd, 2013) and responded to it, it took him a while, this article was online for at least 5 years or so. Obviously his responds was far from “positive” to say the least, something that was expected of course. Would I be labelled a “counter-intelligence agent” as well, as some others who spoke out against the Ancient Solfeggio Frequency story as been told by Dr. Horowitz were?

Well, he finally did, if you’re wondering what he wrote, the you can read his responds to my blog article right here:

Obviously with that many accusations, presumptions and claims, it would be appropriate to set some things straight, I’ve only done some with some things, if you are curious, then you can read my responds to Dr. Horowitz responds to this article right here >


Wikipedia references:

Other references:

Leonard G. Horowitz:

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