A history of pitch standards in piano tuning

In a previous post I explained that "standard" or "concert" pitch means that the note A above middle C has a frequency of 440Hz (cycles per second), and that this was settled upon at a conference in 1939. However, someone recently asked me what pitch would originally have been used for a late nineteenth-century Broadwood grand piano. This is a difficult question to answer, since prior to A=440Hz, there was no single universally agreed standard. So I thought it might be interesting to have a look at the different pitches pianos were tuned to in the past, and how the current standard came about.

The situation can be summed up fairly well by looking at this set of tuning forks, which would date from around a hundred years ago. These are "C" forks which probably would have been used by a piano tuner in the early part of the twentieth century, and there are four different pitches as inscribed on the side of the prongs:

C 517.3 Continental
C 522 New Philharmonic
C 528 Medium
C 540 Old Philharmonic

An set of tuning forks (left) used about a hundred years ago. Two modern forks (C523.3 and A440) are on the right.

It seems to have been a feature of the British piano trade that people were traditionally (and commonly still are) taught to tune using middle C as the reference note (although the forks are actually an octave above this). If we recalculate these frequencies (assuming equal temperament) to values for the note A, which is the generally accepted standard for orchestral tuning, we get A=435Hz, A=439Hz, A=444Hz and A=454Hz (none of these corresponding to modern standard pitch, though "New Philharmonic" is close). From the fact that tuners were carrying these sets of forks around, it would seem likely that these may all have been used at various times depending on the requirements of the customer, and no doubt all of this caused considerable confusion!

To work out the origin of all these pitch standards, we should transport ourselves back into the late eighteenth century, when pianos were becoming widely produced and available for the first time. It should be noted that during this period, there was no standardization of pitch. At the time, absolute pitch could only be measured with limited accuracy - for example, the Italian mathematician, Vittorio Francesco Stancari (1678-1709) had experimented with a toothed wheel as a tone generator. It should also be mentioned in passing that the French mathematician Joseph Sauveur (1653-1716), who worked extensively on acoustic theory, was an early advocate of pitch standardization and in 1713 proposed that middle C should be 256Hz (known as "scientific" or "philosphical" pitch as each "C" has a frequency which is a power of 2), which would correspond in an equally tempered tuning to A=430.54Hz. Apparently, Sauveur's efforts were not particularly welcomed by musicians in his own time, and this pitch has never been widely used as a musical standard (though Italian musicians briefly adopted something similar in 1881, actually A=432Hz, before agreeing to the A=435Hz at the Vienna conference of 1885); however, medical tuning forks, employed for the measurement of hearing, are quite commonly found at this frequency.

The tuning fork had been invented in 1711 by John Shore (1662-1752), a prominent British musician, so it would have been possible to have a convenient portable reference of relative pitch from this time onwards, and it may have had at least some effect in reducing the enormous range of standards in use. A fork made by Shore, which he gave to the composer Handel, still exists today and has a frequency of A=422.5Hz. A fork belonging to the instrument maker Johann Andreas Stein in the 1780s, whose pianos were played by Mozart, comes in at a similar value of A=422Hz, so this is likely a tuning that would have been familiar to musicians of this period. However, there was no consistency - some church organs built during the period have A as low as 390Hz, and some chamber instruments (according to contemporary measurements) were as low as around 410Hz. At the other end of the scale, some organs in Germany that were played by Bach have A as high as 480Hz - a difference in pitch of nearly a major third!

Nonetheless, it seems quite likely that, allowing for significant variations, the pitch of Shore's tuning fork was fairly similar to what might have been used in the early days of piano tuning. Several tuning forks survive from the early nineteenth century - for example a tuning fork used by John Broadwood & Sons, piano makers, from 1800 is equivalent to approximately A=423Hz (it's actually a C-fork) and some from the 1820s give A=428Hz. However, in the first half of the nineteenth century, a trend became very apparent: pitch used by instrumental performers, especially orchestras, was getting higher and higher, a phenomenon often described as "pitch inflation". It is possible that one factor in this trend was a set of musical instruments presented by Tsar Alexander of Russia to the Austrian Army on the occasion of the Congress of Vienna in 1814, tuned to a higher pitch than was normal for the time. The use of higher pitches and wind instruments or increased tension on strings gives a more "brilliant" sound with more overtones, and in the course of the quest for this, pitch inflation continued unabated. (It is true that pianos too can sometimes have a brighter tone when the pitch is raised, but of course they are not normally tuned by the performer, but rather by someone who does not want to break any strings!)

Pitch inflation and tuning in the nineteenth century

In any case, the early nineteenth century was the heyday of the orchestra and by mid-century pitch inflation was almost out of control, with some orchestras (such as the London Philharmonic) going higher than A=450Hz - a full semitone above what it was in Mozart's time. Needless to say, this development was received with much chagrin by singers, who were straining their vocal chords trying to reach the ever-higher notes. The situation became so bad that in 1859, the French government decided to act and declared that by law A=435Hz was in future to be the standard for musical performances. This standard was known as the "Diapason Normal" (diapason is French for a tuning fork), but in English-speaking countries was normally referred to as French Pitch, Continental Pitch (as in our set of tuning forks), or International Pitch (this last term should be used today with caution as it may be taken to mean International Concert Pitch, or A440). This pitch was adopted by several other countries (it was adopted at an international conference in Vienna in 1885) and remained an important standard until the adoption of A440 in 1939; however it was by no means universally accepted, possibly not even in France, and certainly not elsewhere, e.g. the Vienna opera is recorded as using A=447Hz in the 1870s. In particular, the British held out at the "Philharmonic Pitch" of approximately A=452Hz (it is actually a bit of a moveable feast) for orchestral performances until almost the end of the nineteenth century.

Another development around this time is also worthy of mention: Johann Scheibler, a German silk manufacturer who was a self-taught acoustician, invented a "tonometer", a set of 56 carefully calibrated tuning forks, arranged by carefully counting "beats" between adjacent pairs and measuring them using a pendulum or metronome. This enabled a more accurate measurement of absolute pitch than had previously been the case. At a conference of German scientists attended by Scheibler in 1834, A=440Hz was proposed as a standard pitch, although it was not widely adopted - however it may have been used in some parts of Germany (e.g. the Dresden Opera in 1862), and by the Streicher piano company. Incidentally, around the same time as Scheibler, a Frenchman called Felix Savart was experimenting with toothed wheels as more accurate tone generators.

However, this does not really answer our question of what piano tuners were doing in the latter part of the nineteenth century. There is some evidence from records and tuning forks of common practice in the UK. The Broadwood company was using three different pitches which seem to have stayed very roughly the same - a "low" pitch, starting at around A=433Hz but which eventually seems to have settled down to the French standard of A=435Hz, a "medium" pitch of around 446Hz, which eventually moved to around A=444Hz, and a "high" pitch equivalent to the Philharmonic Pitch (later referred to as "Old Philharmonic") which varied between around A=452Hz and A=455Hz.

Around the 1860s, Broadwood tuners were issued with sets of three "C" forks, marked "Vocal", "Medium", and "Philharmonic", corresponding to tunings of A=435Hz, A=445Hz and A=452Hz respectively. The low pitch was presumably used for singing, the medium pitch probably for standard domestic tunings and the high pitch perhaps for concerts or playing with other instruments. These three pitches are the ancestors of three of the four tuning forks in our early twentieth century set: the Continental (A435), Medium (A444) and Old Philharmonic (A454). 

The final one derives from 1896 - under Sir Henry Wood, when the famous Promenade Concerts were first instigated, the very high orchestral pitch was abandoned, supposedly in favour of A435. However, this was incorrectly assumed to apply to a temperature of 15⁰C (59⁰F) - in fact it was an absolute standard. In a concert hall at 20⁰C (68⁰F) the pitch of brass instruments tuned to A435 at 15⁰C would rise to approximately A=439Hz, so this was adopted as the new standard, and became known as the "New Philharmonic" pitch, with the previous, higher, pitch now referred to as "Old Philharmonic". This was still not an end to the matter, as the British Army continued to hang on to the old higher pitch for its military bands until the 1920s. The cost of replacement of the older instruments tuned to the higher pitch may have been a significant factor in this.

In his book "A Treatise on the Art of Pianoforte Construction" of 1916, Samuel Wolfenden, chief designer for the well-known firm of George Rogers and Sons, describes the same four pitch standards, the only difference being that the "medium" pitch is given as C=530Hz (A=445.7Hz), which he describes as the old Society of Arts pitch (from the Royal Society for the Encouragement of Arts, Manufactures and Commerce), and also notes that both the Medium and Old Philharmonic pitches varied slightly because of "slight concessions to the conditions under which pianofortes are used in combination with wind instruments at high temperatures". He describes the Continental pitch of A435 as "general throughout Europe" and said that there had been many years of contention among musicians due to the use of the high pitch [Old Philharmonic] which was obnoxious to vocalists; he comments that it is "retained because used by military bands...because of the great expense of new instruments." He also mentions in passing that "quite recently an influential committee of musicians and manufacturers in America has established a pitch founded upon A=440 v.s. [vibrations per second]."

In an article to the "Organist and Choirmaster" magazine of July 1899, the piano manufacturers John Broadwood & Sons put themselves at the forefront of the drive to move to the then newly established standard of A439, commenting that: "So far, pianoforte makers have held aloof and made no effort to secure uniformity in regard to the pitch at which their productions are tuned. Some favour one pitch and some another. The consequence is that if a visit be made to any of the large emporiums in provincial towns where pianos are sold, the visitor is hampered in his choice by seldom finding all pianos in the same show-room tuned to a uniform pitch." The letter continued: "In regard to concert grands, the want of uniformity in regard to pitch is serious, and necessitates makers keeping a double number of instruments." They had written to other manufacturers about this matter, which seems to have led to the use of the "New Philharmonic" pitch as at least an informal standard for British piano tuners around this time.

A selection of three forks used in the middle of the twentieth century - A439 (marked New Philharmonic) on the left, A440 (marked British Standard) in the middle and A452.5 on the right.

Another set of forks from a piano tuner's kit around the middle of the twentieth century contains three "C" forks. The one on the left, labelled "New Philharmonic" is equivalent to A=439Hz as one would expect, the middle one is an A=440Hz fork, and the one on the right is a slightly different version of an Old Philharmonic fork, A=452.5Hz. In her 1933 book "The Piano-forte, its history traced to the Great Exhibition of 1851", Rosamond Harding describes the use of the New Philharmonic A439 pitch as "almost as universal in this country as on upon the continent, though pianos are occasionally tuned to the old Philharmonic pitch, a' 454 (c'' 540)." (The idea that the New Philharmonic and Diapason Normal were in some sense the same seems to have persisted for a long while).

The road to A440

So having meandered through the many twists and turns of the various old tuning standards, it seems appropriate to come to the question of how A440 came about. It appears that in the United States, there was relatively little pitch standardization with A continuing to creep upwards, getting to somewhere between A=455Hz and A=460Hz (Steinway were apparently using A=457Hz in 1890). An early advocate of A440 as a standard was J C Deagan, proprietor of a company producing percussion instruments, notably including tuning forks. He described it as the "higher German pitch" (in contrast to A435), but there also seems to have been an argument along the same lines as the New Philharmonic Pitch - that when concert halls were heated (in this case to 72⁰F from the 59⁰F on which the French standard was supposedly based), the pitch of wind instruments rises to A=440Hz. The American Federation of Musicians adopted this in 1910, and it seems to have gradually gained acceptance, being generally used by the US recording industry after 1925 and ratified by the American Standards Association in 1936.

In May 1939, a meeting at Broadcasting House, London (facilitated by the British Standards Institute) was held, attended by delegates from France, the Netherlands, Germany and Italy, with representations from Switzerland and the United States sent by telegram. It was this conference that eventually agreed on A=440Hz as the new standard, although some British representatives were still in favour of A=439Hz. It seems that the British electrical engineer James Swinburne (1858-1958), a keen musician, may have played a role in advocating A440 as it is easier to subdivide mathematically. Apparently piezo-electronic generators of the time (as used by the BBC) worked on the basis of a tone which was divided or multiplied by particular numbers and as 439 is a prime number, 440 was easier to work with in this respect. To what extent this really was a factor in the decision I don't really know, but in the end 440Hz was agreed upon, practically the last thing anyone across Europe reached consensus about before the outbreak of the Second World War. In 1955 the International Organization for Standardization confirmed this standard as ISO 16, and reaffirmed it in 1975.

Well, with agreement reached, that should bring us to the end of our discussion... but in fact, it does not. Notwithstanding the fact that A440 is the only agreed international standard for tuning musical instruments, today the majority of orchestras in the world do not tune to this frequency (jazz musicians generally do, however). In fact, there is a website here (should you ever need to know) giving the tunings used by various orchestras in countries around the globe.

Firstly, it would be worth saying a little about the lower pitch standards in use today. For early music, both A=430Hz and A=415Hz (sometimes called Baroque pitch) are often used. These do not reflect the exact tunings actually used in the Baroque period (as there were no standard tunings), but rather are convenient compromises. Both are probably closer to the actual (albeit inconsistent) tunings that were used, but an additional consideration is that it is somewhat safer to tune historic instruments (at least in the case of harpsichords or early pianos) below A440. The 415Hz tuning is also highly convenient as it is exactly a semitone below modern standard pitch and therefore can be played with modern or standardly tuned instruments if the parts are transposed by a semitone.

Leaving the question of early music aside, however, it is clear that many orchestras tune to 441, 442, 443 or 444Hz, in search of that same brilliance of sound as their nineteenth-century predecessors. To understand this, we should consider the old French pitch of 1859 - the important thing is that, although many musicians ignored it, up until 1939 it had the important effect of putting a brake on pitch inflation. In fact, the whole thing is a bit like inviting people to turn up to a party at 7.30 when you actually want them to come at 8, since if you asked them to come at 8 they would actually come at 8.30. In the same way, whatever pitch standard is set, some people will try to push the envelope, but normally only so far.