Bass Clarinet (Fr. clarinette basse; Ger. Bass-Klarinette; Ital. clarinetto basso or darone), practically the A, B♭ or C clarinet speaking an octave lower; what therefore has been said concerning the fingering, transposition, acoustic properties and general history of the clarinet (q.v.) also applies to the bass clarinet. Owing to its greater length the form of the bass clarinet differs from that of the clarinets in that the bell joint is bent up in front of the instrument, terminating in a large gloxinea-shaped bell, and that the mouthpiece is attached by means of a strong ligature and screws to a serpent-shaped crook of brass or silver. The compass of the modern orchestral bass clarinet is in the main the same as that of the higher clarinets in C, B♭ and A, but an octave lower, and therefore for the bass clarinet in C is ; for the bass clarinet in B♭ the real sounds are one tone, and for the bass clarinet in A 1&FRAC12; tone lower, although the notation is the same for all three.
Sometimes the treble clef is used in notation for the bass clarinet. It must then be understood that the instrument in C speaks an octave lower, the bass clarinet in B♭ a major ninth and the bass clarinet in A a minor tenth lower. The tenor clef is also frequently used in orchestral works.
The quality of tone is less reedy in the bass clarinet than in the higher instruments. It resembles the bourdon stop on the organ, and in the lowest register, more especially, the tone is somewhat hollow and wanting in power although mellower than that of the bassoon. In the lowest octave the instrument speaks slowly and is chiefly used for sustained bass or melody notes; rapid passages are impossible.
The modern orchestral model may be fitted with almost every kind of key-mechanism, including the Boehm, and the degree of perfection and ingenuity attained has removed the all but insuperable difficulties which stood in the way of the original inventors who, not understanding key-work, made many futile attempts to bridge the necessarily great distance between the finger-holes by making the bore serpentine, boring the holes obliquely, etc.
The low pitch of the bass clarinet (8 ft. tone) contrasted with the moderate length of the instrument - whose bore measures only some 42 to 43 inches from mouthpiece to bell, whereas that of the bassoon, an instrument of the same pitch, is twice that length - is a puzzle to many. An explanation of the fact is to be found in the peculiar acoustic properties of the cylindrical tube played by means of a reed mouthpiece characterizing the clarinet family, which acts as a closed pipe speaking an octave lower than an open pipe of the same length, and overblowing a twelfth instead of an octave. This is more fully explained in the articles Clarinet and Aulos.
The construction of the bass clarinet demands the greatest care. The bore should theoretically be strictly cylindrical throughout its length from mouthpiece to bell joint; the slightest deviation from mathematical accuracy, such as an undue widening of the bell from the point where it joins the body to the mouth of the bell, would tend to muffle the lower notes of the instrument and to destroy correct intonation.
The origin of the bass clarinet must be sought in Germany, where Heinrich Grenser of Dresden, one of the most famous instrument-makers of his day, made the first bass clarinet in 1793. The basset horn (q.v.) or tenor clarinet, which had reached the height of its popularity, no doubt suggested to Grenser, who was more especially renowned for his excellent fagottos, the possibility of providing for the clarinet a bass of its own. One of these earliest attempts in the form of a fagotto, stamped "A. Grenser, Dresden," with nine square-flapped brass keys working on knobs, is in the Grossherzogliches Museum at Darmstadt and was lent to the Royal Military Exhibition, London 1890. Two other early specimens, belonging originally to Adolphe Sax and to M. de Coussemaker, are now respectively preserved in the museums of the Brussels Conservatoire and of the Berlin Hochschule (Snoeck Collection). The tubes are of great thickness and the holes are bored obliquely through the walls. Both instruments are in A.
Attempts were made in Italy to overcome the mechanical difficulties by making the bore of the bass clarinet serpentine. A specimen by Nicolas Papalini of Pavia in the museum of the Brussels Conservatoire has the serpentine bore pierced through two slabs of pear-wood; the two halves, each forming a vertical section of the instrument, are fitted together with wooden pins. The outside length is only 2 ft. 3&FRAC12; in. and there are nineteen finger-holes.
Joseph Uhlmann of Vienna constructed a bass clarinet, also termed "bass basset horn," with twenty-three keys and a compass from B♭ through four complete octaves with all chromatic semitones. These instruments resemble the saxophones (q.v.), having the bell joint bent up in front and the crook almost at right angles backwards, but the bore of the saxophone is conical.
Georg Streitwolf (1779-1837), an ingenious musical instrument-maker of Göttingen, produced in 1828 a bass clarinet with a compass extending from A♭ to F, nineteen keys and a fingering the same as that of the clarinet with but few exceptions. In form it resembled the fagotto and had a crook terminating in a beak mouthpiece. The Streitwolf bass clarinet was adopted in 1834 by the Prussian infantry as bass to the wood-wind. Streitwolf's first bass clarinets were in C, but later he constructed instruments in B♭ as well. Like the basset horn, Streitwolf's instruments had the four chromatic open keys extending the compass downwards to B♭. The tone was of very fine quality. One of these instruments is in the possession of Herr C. Kruspe of Erfurt, and another is preserved in the Berlin collection at the Hochschule.
It was, however, the successive improvements of Adolphe Sax (Paris, 1814-1894), working probably from Grenser's and later from Streitwolf's models, which produced the modern bass clarinet, and following up the work of Halary and Buffet in the same field, he secured its introduction into the orchestra at the opera. The bass clarinet in C made its first appearance in opera in 1836 in Meyerbeer's Huguenots, Act V., where in a fine passage the lower register of the instrument is displayed to advantage, and later in Dinorah (Le pardon de Ploermel). Two years later (1838) at the theatre of Modena a bass clarinet by P. Maino of Milan, differing in construction from the Sax model, was independently introduced into the orchestra. Wagner employed the bass clarinet in B♭ and C in Tristan und Isolde, where at the end of Act II. it is used with great effect to characterize the reproachful utterance of King Mark, thus:
 See Captain C. R. Day, Descriptive Catalogue (London, 1891), No. 266, p. 125.
 See Victor Mahillon, Catalogue descriptif, vol. ii. (1896), pp. 224-226, No. 940.
 See Captain C. R. Day, op. cit. p. 123, pl. v. B. and p. 123, No. 262.
 See Dr Schafhäutl's report on the Munich exhibition, Bericht der Beurtheilungscommission für Musikinstrumente (Munich, 1855), P. 153.
 See Allgemeine musikalische Zeitung (Leipzig, 1834), Bd. xxxvi. March, p. 193.
 See Wilhelm Altenburg, Die Klarinette (Heilbronn, 1904-1905), p. 33.
 See W. Altenburg, op. cit. p. 34.
 Orchestral score, p. 284.