What is Multiphonics?
According to the Grove Music Online, multiphonics are "sounds generated by a normally monophonic instrument in which two or more pitches can be heard simultaneously". The term 'multiphonics' is normally used when referring to chords played on a woodwind or brass instrument. The woodwinds or brass instruments are monophonic instruments that can usually produce only one note. However, by altering the way of blowing, fingerings or by using voice, it is possible to produce more notes at the same time. These sounds are called multiphonics.
Multiphonics has been in use since the eighteenth century when horn players would produce chords of three or four notes. This is done by simultaneously humming or singing another note above or below the note of the horn. If the sung note was strong enough, the two sound waves interfered with one another and two other notes can be noticed below and above the original notes.
For example, by playing a G (sounding C) and humming G (actual sound) a fifth above, a C that is an octave below and an E that is sixth above the G should sound, creating a chord. This example is illustrated below.
It is generally found that, of the two summation notes the lower is more prominent, although both are not likely to be heard above a mezzo forte dynamic level. To achieve optimum dynamics, the blown and hummed notes should be at a steady pitch, at the true interval and at approximately the same dynamic level. It also helps if the timbre of the voice matches the timbre of the horn as much as possible. If the interval between the notes is too small, the interference results in a rhythmic beating which breaks up the tone and pitch. If the notes are only a fraction of a tone apart, the produced beat is slow, and accelerates as the interval widens.
An example of horn multiphonics can be found as early as 1806, in the Horn Concerto by Carl Maria von Weber with a slightly unearthly and rather startling effect,
as illustrated below
Ex.2 Cadenza from final movement, Carl Maria von Weber: Concertino for Horn and Orchestra
listen to MP3 sample played by Wim van de Haak
In general, the larger the bore of the instrument, the better the multiphonics work. Therefore it is easier to create multiphonics on the tuba or bass trombone than on a trumpet.
A musical tone exists as a fundamental tone with its own series of overtones, as a part of the overtone series, and as a part of the tonal spectrum of the slide position or the fingering with which it is produced.
For example, a trombone pitched in B flat has the following overtone series in the first position:
Ex.3 Overtone series B flat
When the trombone slide extends to the second position another overtone series is created, as illustrated in Ex.4:
Ex.4 Overtone series A
So when the trombone plays an F in the first position it has all the overtones of that pitch. At the same time, it has the third partial of the overtone series of B flat. If the same F would be to be played with the slide in sixth position, the F would be then the fourth partial of the overtone series based on F.
Ex.5 Overtone series F
Using these overtone series, a resulting multiphonic can be easily calculated as the sum of the relationship between the tone played and the tone sung. When playing the F and simultaneously singing a D above, the multiphonic will be B flat. The F is the third partial and the D is the fifth partial, so with the simple arrhythmic of equation 3+5=8, the B flat which is the eighth particle can be predicted. An occasional fourth note is then the subtraction of the two generating tones. In this case, 5-3=2 would be the second particle, or the low B flat.
Ex.6 Chord 3+5=8
Multiphonics are relatively easier to play for the low brass instrument. , This makes it possible to create chords deliberately and extend the use of multiphonics to a chorale in full harmony with a single brass instrument as in the example below
listen to MP3 sample played by Klaas van Slageren
On a woodwind instrument multiphonics can also be achieved by splitting a tone played by regular fingerings in the low register. This is done by altering the embouchure so that a fundamental tone sounds simultaneously with a selection of its harmonics. Similarly, in the upper register, regular notes can be lipped down to produce the undertones. This results in harsh, electronic-sounding multiphonics. The example below is a chart of conventional fingerings for clarinet.
Ex.8 Multiphonics using conventional fingerings for clarinet
Another way to produce multiphonics on a woodwind is by choosing an unconventional fingering pattern for which the resonant modes of the air column are not harmonically related. The player may then be able to simultaneously sustain two inharmonically related tones, each based on one of the air column modes. The interaction with the sound generator (reed, air jet or lips) mixes the two tones, giving the additional sum and difference tones. The result is a rich complex of generally inharmonic partials. Such a sound may be perceived as a stable chord with several pitches, or as a tone cluster with periodically fluctuating loudness and timbre. Fingering systems for producing multiphonics have been developed for most wind instruments. The unconventional fingering multiphonics are used extensively in new music because of the accuracy with which the upper and lower notes can be pitched. The example below is a chart of uncoventional fingerings for clarinet.
Ex.9 Multiphonics using unconventional fingerings for clarinet
Books, dissertations and articles about clarinet multiphonics have been published since 1967. These works deal with fingerings, notations, analyses of specific compositions, and descriptions of various new techniques. More recently, there are works dealing with multiphonics in a pedagogical fashion and deal with the mastery of technique.
Multiphonics have gained popularity along with other experimental techniques among composers and performers. The interest in new compositional devices, stemming from the collaboration of composers and performers during the late 1950s and early 1960s, resulted from a desire to expand the traditional resources of wind instruments to include unconventional elements alongside conventional elements. As composers continued to develop their art, adventurous performers explored the full potential of their instruments and opened up a vast area of formerly unused sounds.
Multiphonics in itself is not such a sensational or a shocking idea because it is in our human nature to desire a fuller, richer and complex harmony. In general, monophonic instruments sought out ways to fulfil this desire on their own. In the early days this has been seen as a mere 'parlour trick'(qtd. In Gregory, 141) or later on as a "gimmick to add excitement to a solo or to achieve special sounds in conjunction with electronic effects." (Militello, 274) Nowadays it is widely used in all wind instruments featuring and functioning musically on diverse levels. It is also considered "a great stimulant for the imagination and creative sense, allowing the player a freedom and new avenue of expression". (Militello, 275)
The phenomenon of multiphonics ha