It is a double reed instrument of the oboe family, but with a wider bore and hence a heavier and more penetrating tone. It is pitched an octave below the oboe and furnished with an additional semitone taking its range down to A. It was intended to provide a broad oboe-like sound in the middle register of the swollen orchestrations of the turn of the twentieth century. In the orchestral repertoire it is generally used as the bass of an oboe section incorporating the oboe and the cor anglais (English horn), filling the gap between the oboes and bassoons.
The Heckelphone is approximately four feet in length, and is quite heavy: it rests on the floor, supported by a short metal peg attached to the underside of its bulbous bell. (An alternate second bell, called a "muting" bell, is also available, which serves to muffle the instrument for playing in a small ensemble.) This arrangement is unique among double-reed instruments. It is played with a large double reed that more closely resembles a bassoon reed than an oboe reed.
Smaller piccolo- and terz-Heckelphones were developed, sounding in E-flat and F above the written tone, but only around a dozen were made.
The first use of the Heckelphone was in Richard Strauss's 1905 opera Salome. The instrument was subsequently employed in the same composer's Elektra, Eine Alpensinfonie (though this part frequently calls for notes that are below the range of the Heckelphone), Josephslegende and Festliches Präludium. It was adopted as part of the large orchestral palette of such works as Edgard Varèse's Amériques (1918-1921) and Arcana (1925-1927).
The Heckelphone is often confused with Lorée's redesigned hautbois baryton which was introduced in 1889, the term "bass oboe" being widely used to describe both instruments. Among English composers of the early-20th century there was some vogue for the use of a "bass oboe", for example in Gustav Holst's orchestral suite The Planets (1916), as well as in several works of Frederick Delius (A Mass of Life, 1904-1905; Dance Rhapsody No. 1, 1908), Arnold Bax's Symphony No. 1 (1921), Havergal Brian's Gothic Symphony (1919-1927) and Symphony No. 4 (Das Siegeslied), and in the original instrumentation of Ralph Vaughan Williams' A London Symphony (1912-1913). However, it is not in all cases clear which of the two instruments is intended—indeed, it is possible that sometimes the composers themselves were unclear as to the distinction. Strauss, however, mentions both instruments in his 1904 revision of Hector Berlioz's Traité d'instrumentation et d'orchestration moderne, and (like Varèse) specifies the instrument by name in his orchestral scores, so preventing any ambiguity.
Recent works to use the Heckelphone include the orchestral work Asyla (1997) by the British composer Thomas Adès. The Heckelphone is also featured in the orchestal music of Finnish composer Kalevi Aho. It is heard in his operas Insect Life (1985-87), The Book of Secrets (1998), and Before We Are All Drowned (1995/99), in the Symphonies no. 6 (1979-80), 11 (1997-98), and 13 (2003), and in his Piano Concerto no. 1 (1988-89), Contrabassoon Concerto (2004-05) and Oboe Concerto (2007).
For all its potential in adding weight to the lower registers of the woodwind section, the Heckelphone remains a rarity on the orchestral scene—only about 150 Heckelphones have been produced, of which around 100 are believed to be extant—and is seldom carried on the regular roster of professional orchestras. Competent players are thus rare. The most prominent American heckelphone players now are Mark Perchanok and Andrew Shreeve, both of New York City. Shreeve plays regularly with the Metropolitan Opera while Perchonak has performed many new and older compositions for the instrument and has recorded with the Paul Winter Consort. Other notable American players include Robert Howe of Massachusetts, most known for recital work, and Arthur Grossman of Seattle, Washington.
The first annual meeting of the North American Heckelphone Society took place on August 6, 2001 at the Riverside Church in New York City, with six Heckelphonists in attendance—possibly the first occasion upon which six such instruments had been assembled under one roof. Later meetings have included as many as ten instruments. The group has met annually in New York in the autumn.
The centennial of the Heckelphone in 2004–5 led to the publication of a number of articles on the instrument in organological journals. Among these were two in the German-language "Rohrblatt" by the Cologne player Georg Otto Klapproth; a comprehensive review article by Robert Howe and Peter Hurd, "The Heckelphone at 100", in the 2004 Journal of the American Musical Instrument Society; and a two-part article by Michael Finkelman in the 2005 issues of The Double Reed.