Brass instrument
The euphonium is a medium-sized, 3- or 4-valve, often compensating, conical-bore, tenor-voiced brass instrument that derives its name from the Ancient Greek word "euphōnos", meaning "well-sounding" or "sweet-voiced" ( "eu" means "well" or "good" and "phōnē" means "sound", hence "of good sound"). The euphonium is a valved instrument. Nearly all current models have piston valves, though some models with rotary valves do exist.
Euphonium music may be notated in the bass clef as a non-transposing instrument or in the treble clef as a transposing instrument in B♭. In British brass bands, it is typically treated as a treble-clef instrument, while in American band music, parts may be written in either treble clef or bass clef, or both.
A person who plays the euphonium is known as a euphoniumist, a euphonist, a euphophonist or simply a euphonium player.
Name.
The euphonium is in the family of brass instruments, more particularly low-brass instruments with many relatives. It is extremely similar to a baritone horn. The difference is that the conical bore size of the baritone horn is typically smaller than that of the euphonium. It is controversial whether this is sufficient to make them two different instruments. In the trombone family large and small bore trombones are both called trombones, while the cylindrical trumpet and the conical flugelhorn are given different names. As with the trumpet and flugelhorn, the two instruments are easily doubled by one player, with some modification of breath and embouchure, since the two have identical range and essentially identical fingering.
The "American baritone", featuring three valves on the front of the instrument and a curved, forward-pointing bell, was dominant in American school bands throughout most of the 20th century, its weight, shape, and configuration conforming to the needs of the marching band. While this instrument is a conical-cylindrical bore hybrid, somewhere between the classic baritone horn and euphonium, it was almost universally labelled a "baritone" by both band directors and composers, thus contributing to the confusion of terminology in the United States.
Several late 19th century music catalogs (such as Pepper and Lyon &amp; Healy) sold a euphonium-like instrument called the "B♭ bass" (to distinguish it from the E♭ and BB♭ bass). In these catalog drawings, the B♭ Bass had thicker tubing than the baritone; both had three valves. Along the same lines, drum and bugle corps introduced the "Bass-baritone", and distinguished it from the baritone. The thicker tubing of the three-valve B♭ bass allowed for production of strong false-tones, providing chromatic access to the pedal register.
Ferdinand Sommer's original name for the instrument was the "euphonion". It is sometimes called the tenor tuba in B♭, although this can also refer to other varieties of tuba. Names in other languages, as included in scores, can be ambiguous as well. They include French "basse", "saxhorn basse", and "tuba basse"; German "Baryton", "Tenorbass", and "Tenorbasshorn"; Italian "baritono", "bombardino", "eufonio", and "flicorno basso". The most common German name, "Baryton", may have influenced Americans to adopt the name "baritone" for the instrument, due to the influx of German musicians to the United States in the nineteenth century.
History and development.
As a baritone-voiced brass instrument, the euphonium traces its ancestry to the ophicleide and ultimately back to the serpent. The search for a satisfactory foundational wind instrument that could support massed sound above its pitch took many years. While the serpent was used for over two centuries dating back to the late Renaissance, it was notoriously difficult to control its pitch and tone quality due to its disproportionately small open finger holes. The ophicleide, which was used in bands and orchestras for a few decades in the early to mid-19th century, used a system of keys and was an improvement over the serpent but was still unreliable, especially in the high register.
With the invention of the piston valve system c. 1818, the construction of brass instruments with an even sound and facility of playing in all registers became possible. The euphonium is said to have been invented, as a "wide-bore, valved bugle of baritone range", by Ferdinand Sommer of Weimar in 1843, though Carl Moritz in 1838 and Adolphe Sax in 1843 have also been credited. While Sax's family of saxhorns were invented at about the same time and the bass saxhorn is very similar to a euphonium, there are also differences—such as the bass saxhorn being narrower throughout the length of the instrument.
The "British-style" compensating euphonium was developed in 1874 by David Blaikley, of Boosey &amp; Co, and has been in use in Britain since then, with the basic construction little changed.
Modern-day euphonium makers have been working to further enhance the construction of the instrument. Companies such as Adams and Besson have been leading the way in that respect. Adams euphoniums have developed an adjustable lead-pipe receiver, which allows players to change the timbre of the instrument to whatever they find preferable. Besson has been credited with introducing an adjustable main tuning-slide trigger, which allows players more flexibility with intonation.
Construction and general characteristics.
The euphonium, like the tenor trombone, is pitched in concert B♭. For a valved brass instrument like the euphonium, this means that when no valves are in use the instrument will produce partials of the B♭ harmonic series. 
Music for the euphonium is generally written at concert pitch in the bass clef, treating the euphonium as a non-transposing instrument like the trombone. Higher passages are sometimes written in the tenor clef. In addition to bass clef euphonium parts, concert band music often includes treble clef euphonium parts in B♭ which sound a major ninth lower than written. In the British-style brass band tradition, euphonium music is always written this way. In continental European band music, parts for the euphonium may also be written in bass clef in B♭, sounding a major second lower than written.
Professional models have three top-action valves, played with the first three fingers of the right hand, plus a fourth valve, generally found midway down the right side of the instrument, played with the left index finger; such an instrument is shown at the top of this page. Such models also have compensating "knuckles" to resolve intonation issues below E2. Beginner models often have only the three top-action valves, while some intermediate "student" models may have a fourth top-action valve, played with the fourth finger of the right hand. Compensating systems are expensive to build, and there is in general a substantial difference in price between compensating and non-compensating models. For a thorough discussion of the valves and the compensation system, see the article on brass instruments.
The euphonium has an extensive range, from E2 to about F4 for intermediate players (using scientific pitch notation). In professional hands this may extend from B0 to as high as B♭5. The lowest notes obtainable depend on the valve set-up of the instrument. All instruments are chromatic down to E2, but four-valved instruments extend that down to at least C2. Non-compensating four-valved instruments suffer from intonation problems from E♭2 down to C2 and cannot produce the low B1; compensating instruments do not have such intonation problems and can play the low B1. From B♭1 down lies the "pedal range", i.e., the fundamentals of the instrument's harmonic series. They are easily produced on the euphonium as compared to other brass instruments, and the extent of the range depends on the make of the instrument in exactly the same way as just described. Thus, on a compensating four-valved instrument, the lowest note possible is B0, sometimes called double pedal B, which is six ledger lines below the bass clef.
As with the other conical-bore instruments, the cornet, flugelhorn, horn, and tuba, the euphonium's tubing (excepting the tubing in the valve section, which is necessarily cylindrical) gradually increases in diameter throughout its length, resulting in a softer, gentler tone compared to cylindrical-bore instruments such as the trumpet, trombone, sudrophone, and baritone horn. While a truly characteristic euphonium sound is rather hard to define precisely, most players would agree that an ideal sound is dark, rich, warm, and velvety, with virtually no hardness to it. This also has to do with the different models preferred by British and American players.
Though the euphonium's fingerings are no different from those of the trumpet or tuba, beginning euphoniumists will likely experience significant problems with intonation, response and range compared to other beginning brass players.
Types.
Compensating.
The compensating euphonium is common among professionals. It utilizes a three-plus-one-valve system with three upright valves and one side valve. The compensating valve system uses extra tubing, usually coming off the back of the three upright valves, in order to achieve proper intonation in the lower range of the instrument. This range being from E2 down to B♭1. Not all four-valve and three-plus-one-valve euphoniums are compensating. Only those designed with extra tubing are compensating. There were, at one time, three-valve compensating euphoniums available. This configuration utilized extra tubing, just as the three-plus-one compensating models did, in order to bring the notes C2 and B1 in tune. This three-valve compensating configuration is still available in British style baritone horns, usually on professional models.
Double-bell.
A creation unique to the United States was the double-bell euphonium, featuring a second smaller bell in addition to the main one; the player could switch bells for certain passages or even for individual notes by use of an additional valve, operated with the left hand. Ostensibly, the smaller bell was intended to emulate the sound of a trombone (it was cylindrical-bore) and was possibly intended for performance situations in which trombones were not available. The extent to which the difference in sound and timbre was apparent to the listener, however, is up for debate. Michele Raffayolo of the Patrick S. Gilmore band introduced the instrument in the U.S. by 1880, and it was used widely in both school and service bands for several decades. "Harold Brasch" (see "List of important players" below) brought the British-style compensating euphonium to the United States c. 1939, but the double-belled euphonium may have remained in common use even into the 1950s and 1960s. In any case, they have become rare (they were last in Conn's advertisements in the 1940s, and King's catalog in the 1960s), and are generally unknown to younger players. They are chiefly known now through their mention in the song "Seventy-Six Trombones" from the musical "The Music Man" by Meredith Willson.
Marching.
Marching euphoniums are used by marching bands and in drum and bugle corps. Typically in a drum corps, there will be two baritone parts and one euphonium part, with the euphonium playing the lower parts comparatively. Some corps (such as the Blue Devils) march all-euphonium sections rather than only marching baritone or a mix of both. In high school marching bands, the two will often be used interchangeably.
Depending on the manufacturer, the weight of these instruments can be straining to the average marcher and require great strength to hold during practices and performances, leading to nerve problems in the right pinky, a callus on the left hand, and possibly back and arm problems. Marching euphoniums and marching baritones commonly have three valves, opposed to the regular euphonium having four.
Another form of the marching euphonium is the convertible euphonium. Recently widely produced, the horn resembles a convertible tuba, being able to change from a concert upright to a marching forward bell on either the left or right shoulder. These are mainly produced by Jupiter or Yamaha, but other less expensive versions can be found.
Five valves.
The five-valve euphonium (non-compensating) is an extremely rare variation of the euphonium manufactured in the late 19th and early 20th centuries by Britain's Besson musical instrument company and Highams of Manchester Musical Instrument Company. 
Higham and Besson's "Clearbore" five-valve euphonium was economical but not widely used.
The Besson five-valve euphonium featured the standard three piston valves horizontally not on top, but had an additional two piston valves off to the side. The standard euphonium has eight possible fingering and non-fingering positions by which sound is produced. The Besson and the Highams "clearbore" model rare fourth and fifth extra "side" valves change the possible fingering and non-fingering positions from eight to thirty-two.
The term 'five-valve euphonium' does not refer to variations of the double bell euphonium made by various brass instrument companies during the same time period. Some of the double-bell euphoniums had five valves, with the fifth valve either not on top with the other four, or by itself