The alto clarinet is a woodwind instrument of the clarinet family. It is a transposing instrument pitched in the key of E♭, though instruments in F have been made. In size, it lies between the soprano clarinet and the bass clarinet. It bears a greater resemblance to the bass clarinet in that it typically has a straight body (made of grenadilla or other wood, hard rubber, or plastic), but a curved neck and bell made of metal. All-metal alto clarinets also exist. In appearance, it strongly resembles the basset horn but usually differs in three respects: it is pitched a whole step lower, it lacks an extended lower range, and it has a wider bore than many basset horns.
The alto clarinet was invented by Iwan Müller and Heinrich Grenser, and Müller was performing on an alto clarinet in F by 1809, one with sixteen keys at a time when soprano clarinets generally had no more than 10–12 keys. Müller’s revolutionary thirteen-key soprano clarinet was developed soon after. The alto clarinet may have been invented independently in America; the Metropolitan Museum of Art has a bassoon-shaped alto clarinet in E♭, cataloged as an “alto clarion,” attributed to an anonymous American maker circa 1820.
The alto clarinet is used mostly in concert bands and plays an important role in clarinet choirs. It is bigger than the B flat clarinet but smaller than the bass, and this instrument plays in the key of E♭. It looks more like a small bass clarinet due to the curve at the bell and the crook in the neck. Alto clarinets also tend to use metal bells and necks, making them look even more like small basses.
Due to its larger size and conical bore, the alto clarinet produces a deeper and more resonant sound that adds depth and character to the woodwind section of an ensemble or orchestra. Its timbre has been described as velvety and expressive, with a captivating blend of woodwind and brass-like qualities.
The alto clarinet can play in the range of concert G2 or G♭2 (in the second octave below middle C, bottom line of the bass clef) to E♭6 (in the second octave above middle C), with the exact upper end of the range depending on the skill of the player. Despite the broad range, the instrument is always scored in the treble clef. Most modern alto clarinets, like other instruments in the clarinet family, have the Boehm system or Oehler system of keys and fingering, which means that this clarinet has virtually identical fingering to the others. The alto clarinet, however, often has an extra key allowing it to play a low (written) E♭, and a half-hole key controlled by the left-hand index finger with a vent that may be uncovered to assist in playing the altissimo register.
The alto clarinet family is comprised of a number of similar instruments. It includes the bass clarinet, the clarinet d’amore, the basset horn, and the contra-alto clarinet. There is a notable alto clarinet solo in Percy Grainger’s wind-band piece Lincolnshire Posy.
Some of the most famous alto clarinet pieces include Georg Abraham Schneider’s two concertos (Op. 90 and op. 105) for Müller’s instrument and orchestra. The alto clarinet band part remains in 20th and 21st-century wind band literature. Band directors looking to add color to a large clarinet section will often move clarinet players to this instrument. Many times the alto clarinet serves an important role in the harmonic scoring of the clarinet section within the broader scope of the concert band.
The alto clarinet is categorized into three levels: student, intermediate, and professional. Student clarinets are usually made of plastic or a composite of rubber and plastic, while intermediate and professional clarinets will usually feature wooden or rubber materials that mimic wood clarinet tones. Wooden clarinets are the best if you want a rich sound from the instrument, so the professional clarinet wins in this category. Clarinet keys are plated with one of two metals: silver or nickel, with a few clarinets featuring Hamilton plating, which is a blend of silver and gold. Each metal type has its benefits and drawbacks and will be more common in some clarinet types over others.