Natural instruments

Heimatklang

Playable tones
with the alphorn

The range of the alphorn is the so-called „natural tone series“ with a range of 12 to 16 tones per alphorn, depending on the tuning. Basically, the longer the alphorn, the more notes can be played!

The mood

The tuning or fundamental tone depends on the length of the horn. Short horns have a higher fundamental tone than longer horns. The length of the fundamental sound wave is therefore shorter than in a long horn. This means that the frequency is higher and a higher tone is produced.

The conical shape and the cup also have an influence on the tuning. If the resonant frequencies are only determined for the conical tube, the overtones are not whole multiples of the fundamental frequency, as is the case, for example, with an ideally thin tube (see experiments with a hose) with a constant diameter. There is a deviation from the natural tone series, other non-harmonic intervals arise. If the resonant frequencies of the whole alphorn are determined (with the cup), the harmonic natural tone series is obtained. This means that the cup corrects the inharmonic tone series to the harmonic natural tone series. This was measured by Rolphe Fehlmann in 1994.

Tone overview for alphorns in various keys with frequencies, accompanied by a piano keyboard for illustration.
Table on the acoustics of alphorns: partial tone ratios and frequencies in comparison, ideal for selecting mouthpieces.

The natural tone series

You can blow different tones with the alphorn. Depending on how strongly you vibrate the lips, a higher or lower tone is produced. The pitch of the sound depends on the frequency at which the lips vibrate. High frequency means high tone, low frequency means low tone. If you look at the waves, a higher frequency produces more peaks and troughs in a certain amount of time than a lower frequency.

In the alphorn, these are pressure surges. The faster the lips vibrate, the more pressure pulses are produced and the higher the tone becomes. However, not every frequency produces a beautiful tone. You can only play the tones of the natural tone series, which are the resonance frequencies of the alphorn.

This series begins with the lowest note, the fundamental. A wave is created with two low pressure bellies at both ends and a pressure node in between. The next higher note creates two pressure nodes. This continues, each next note has one more pressure node than the previous one. This means that the frequency of a tone is a multiple of the frequency of the fundamental tone. This tone sequence is called the harmonic natural tone series.

If you play the natural tone series, you start with the fundamental tone, the second tone is an octave higher, the next a fifth, then a fourth and so on. These intervals are the ratios of the frequencies of two tones of different heights. When playing this series of natural tones, you can immediately hear that some tones sound unusual.

The 7th, 11th (also called Alphornfa on the Alphorn) and 13th natural notes seem a little too high or too low to us. This has to do with the fact that our ear is used to tempered tuning. Here, an octave is divided into 12 identical semitone intervals. As a result, only the octave is a pure interval. All other intervals have a small deviation from the natural frequency.

This deviation is particularly noticeable when you compare the 7th, 11th or 13th natural tone of the alphorn with the corresponding tempered tones of a piano. The tones are slightly different.

The unmistakable alphorn fa

The sound of the alphorn is a purely natural instrument. This characteristic brings out the natural tones in a wonderful way. The very special note is the alphorn Fa, which is the 11th note in the natural tone series (see below). The term „Fa“ comes from the musical scale Do - Re - Mi - Fa - So - La - Si - Do. It therefore refers to the 4th tone. The 4th note in the C major scale is F. However, F cannot be played on the alphorn. If you want to play the note between E (third) and G (fifth), you will hear an „intermediate note“ that lies exactly between E and G. This intermediate note is called „Fa“ on the alphorn. If you delimit the middle between E and G more precisely, you can determine that the alphorn's Fa lies between the F (fourth) and the F sharp (tritone). In other words: the alphorn F flat is neither an F nor an F sharp.

The Alphorn-Fa has a special charm. In the past, the Swiss Yodelling Association long outlawed the Alphorn-Fa, or at least described it as an „undesirable sound“ (sonus non gratus). At competitions for alphorn in Switzerland, the alphorn-Fa was consistently disapproved of. Alfred Leonz Gassmann (see below) used both the alphorn-Fa and the Bb in his compositions. In doing so, he gave the Alphorn tunes a new expressive power which, in a suitable form, has a special appeal. Today there are hardly any compositions that do not include the alphorn bass.

Anyone who has had basic training in brass music will find the unusual alphorn „fa“ difficult to play. The reason for this is that this alphorn „falls off“ the diatonic scale. It is worth giving it a try over a longer period of time: don't play the alphorn for a long time, but „only“ the trumpet, flugelhorn or trombone. Then switch to the alphorn and play the natural scale. You will find that you will find it extremely difficult once you have got used to the melodious alphorn sound with your lips and ear. Many listeners - especially those from brass band circles - even think that the alphorn player is playing the wrong note. If you are an alphorn player, you will soon realize the expressive power of this Alphorn-Fa. In the vocabulary of alphorn players, the term "Alphorn-Fa" is used deliberately. They have almost made this natural sound their own.