An instrument without keys, and the note it can never tune.
Image: Bing Daily Wallpaper | Alphorn player on a grassy slope, Bavaria, Germany (© U. J. Alexander/Shutterstock) | Bing homepage
Open Bing today and you see a man standing on an Alpine meadow, his lips pressed to the end of a wooden pipe. The pipe is much taller than he is. It runs diagonally down to the grass before turning up in a flared bell, like a straightened horn.
It is an alphorn. The common Swiss version is 3.47 meters long.
Begin with something you may never have considered: this pipe has not one key, one valve or one finger hole. A trumpet has three valves, a flute has a row of holes and a piano has 88 keys. The alphorn has none. It is simply a smooth wooden tube.
So how does a pipe with no mechanism play a melody?
It Can Sing Only the Notes It Wants
The answer is that it cannot produce any note at will. It can play only the notes on a fixed list.
The column of air inside the pipe has its own natural rhythms, much like a swing. A swing rises only when each push arrives at its preferred frequency; push too quickly or too slowly and it will not work. The air column behaves the same way. It vibrates coherently only at certain frequencies, known as the natural harmonic series.
The lowest is the fundamental. The others follow at two, three, four and five times that frequency, and so on. The player can only choose which one to excite by changing the tension of the lips: tighten them to jump higher in the series, relax them to drop back down.
The length of the pipe determines how low the fundamental will be. A rough formula is simple:
Fundamental frequency ≈ speed of sound / (2 x pipe length)
At 20 C, sound travels at about 343 meters per second. A 3.5-meter pipe therefore has a fundamental near 50 hertz, close to the keys at the far left of a piano. The longer the pipe, the lower the sound. That rule governs everything from an Alpine herdsman's horn to a flexible tube in a bathroom.
One detail matters: the alphorn's bore is conical, widening gradually from mouthpiece to bell. A cylindrical pipe closed at one end, such as a clarinet, produces only the odd-numbered harmonics - 1, 3, 5, 7 and so on - leaving large gaps. A cone restores the full sequence: 1, 2, 3, 4, 5, with none missing. That is why an alphorn, despite having no mechanism, can play stretches of melody rather than just a few calls. A beginner can produce about 13 harmonics; an accomplished player can reach more than 20.
The Note That Will Not Tune
Now we reach the point of the story.
Match the harmonics against a piano and the first few fit reasonably well. The second is an octave, the third an octave plus a fifth, and the fourth another octave. But at the 11th harmonic, something goes wrong.
It falls halfway between F and F-sharp: to be exact, 48.7 cents below F-sharp and 51.3 cents above F. A semitone contains 100 cents, so this note sits almost exactly at the midpoint, belonging to neither side. There is no such key on a piano, no such note in ordinary staff notation, and no assigned place for it in the world of 12-tone equal temperament.
The Swiss have a name for it: Alphorn-Fa.
The interesting part is that they have never tried to tune it away. Switzerland Tourism calls it the "famous alphorn fa." Traditional pieces deliberately include it. It is the instrument's signature, not a defect.
The seventh harmonic is similarly about 31 cents below the equal-tempered minor seventh, while the 13th is about 40 cents sharp. These deviations are not failures of craftsmanship or the result of damp wood. They are the difference between integer ratios and equal temperament, a property of mathematics that appears in every pipe of this kind, whoever made it and whenever it was built.
In other words, this wooden pipe reminds its player every day that it grew out of nature; it was not calibrated in a factory.
A Crooked Tree
The instrument is made from spruce. Traditionally, the graceful upturn of the bell was not produced by bending the wood. A maker climbed a steep hillside and found a tree whose base had been forced by the terrain to curve naturally, then hollowed the horn along that inherited arc. Modern alphorns are usually made in three sections so they can be taken apart and carried in a car.
Many claims circulate about how far their sound carries. I could not find a reliable measurement accompanied by a method. Every source simply says "several kilometers" without explaining how the distance was established, so no figure is given here. One general physical fact is secure: low-frequency sound attenuates more slowly in air than high-frequency sound.
It Almost Disappeared
The instrument's history is more complicated than the image of an unbroken Alpine tradition suggests.
The earliest surviving written record dates to 1527, in an account book from St. Urban's Abbey in Switzerland. The entry reads, "Einem Walliser mit Alphorn" - a payment to a man from Valais with an alphorn. In 1556, the naturalist Conrad Gessner wrote the first detailed description. He gave its length as 330 to 340 centimeters, almost exactly the same as today.
Then it nearly vanished. After 1800, cheesemaking in the high Swiss Alps changed. Small family dairies in isolated mountain huts gave way to large cooperative village cheese factories. Herdsmen no longer had to spend long periods alone at high altitude, and no longer needed a tool for calling across valleys.
The depth of the decline can be measured by a painful pair of numbers. An alphorn competition at the 1805 Unspunnen Festival drew two entrants. When it returned in 1808, only one appeared, and he took every prize without facing a competitor.
The usual story describes those festivals as the beginning of an alphorn revival. But the numbers show that they were really evidence of the decline hitting bottom. Revival had to wait another 20 years. In 1826 and 1827, Niklaus von Mülinen made several horns, lent them to strong local singers in Grindelwald and personally taught them to play. In 1827, the musicologist Joseph Fétis declared the alphorn "Switzerland's national instrument."
Sometimes a "tradition" is a thread rejoined just before it breaks.
But It Is Not Really an Oktoberfest Instrument
Bing's title for today's image is "Alpine Sounds at Oktoberfest." The 2026 Oktoberfest does indeed open today, but one distinction matters.
I checked the official musical events at the festival. The largest is the Platzkonzert der Wiesnwirte, the open-air concert where bands from all the major tents play together. Every available account describes its instrumentation as a traditional Bavarian brass band: trumpets, horns, trombones, tubas and clarinets. No official material lists the alphorn among them.
That is not surprising. The alphorn is a herdsman's instrument found across the Alps, in Switzerland, Austria and southern Germany. A Bavarian church altarpiece from 1568 shows a player, so its presence in Bavaria is entirely authentic. But it is not central to Oktoberfest's musical tradition. The festival's underlying sound is brass band music.
The photograph shows "the sound of the Alps," not "the sound of Oktoberfest." Both are real; they are simply not the same thing.
Why Today?
The 191st Oktoberfest opens on September 19, 2026. It runs through Sunday, October 4.
Notice the edition number. The first festival was held in 1810, 217 years ago, but 2026 brings only the 191st. Cholera, the Austro-Prussian War, the Franco-Prussian War, both world wars, hyperinflation and the COVID-19 pandemic interrupted it repeatedly. The gap of more than 30 years between age and edition number is itself a ledger of modern European history.
The opening ritual has changed little in more than two centuries. At exactly noon local time - 6 p.m. in Beijing - inside the Festhalle Schottenhamel, Munich's mayor drives the tap into the first barrel of beer and calls, "O'zapft is!" - "It's tapped!" At the same moment, beside the Bavaria statue at the far end of the grounds, 12 gun salutes signal to every other tent that beer may be served. This year Mayor Dominik Krause will preside for the first time since taking office.
The first festival in 1810 was really an after-party for a wedding. Crown Prince Ludwig married Princess Therese, and Munich's citizens were invited to celebrate on a field outside the city. The main event was a horse race: 30 horses over a 3,400-meter course. The field became known as the Theresienwiese, and Oktoberfest is still held there.
Tibet Has a Three-Meter Pipe Too
Now move the map east.
Tibetan Buddhist monasteries use an instrument called the dungchen, generally about 3 meters long, with the largest exceeding 5 meters. Made of copper, brass or silver, it telescopes into nested sections.
The important point is that it too has no finger holes and no valves.
Grinnell College in the United States holds one in its instrument collection. The museum's description is explicit: because the instrument has neither finger holes nor valves, it produces "at most three" pitches - the fundamental corresponding to the tube's length and its first two overtones, the first an octave above and the second a 12th, or an octave plus a fifth.
The physics is the same: the same harmonic series and the same limit that lets a player select notes but not create new ones. Yet the two cultures made entirely different choices. Swiss herdsmen developed more than a dozen steps of the series into melody. Tibetan monks use only its lowest two or three, producing a deep, nearly motionless roar.
Physics decides how many notes a pipe can produce. People decide which ones to use.
Sources: Swiss Alphorn Association; Switzerland Tourism; naturtoene.ch alphorn tutorial; swissinfo feature on alphorn acoustics; University of New South Wales, brass acoustics; Oktoberfest official website; muenchen.de opening ceremony page; muenchen.de festival concert page; Grinnell College musical instrument collection, dungchen; and Crawford, American Journal of Physics, 1974