In the first half of the 18th century, public concerts became popular, and the size of the concert halls made new demands on instruments and performers alike. By 1750 instrumental music performed by large ensembles flourished in Paris, Frankfurt, Hamburg, and Vienna. Sammartini was developing symphonic forms in Milan. In addition to strings, he included horn parts and implied that a keyboard with a bass instrument be used for the continuo. He established a direction in musical form that Haydn would follow.
Georg Monn of the Viennese school was influential, as was Wagenseil. In his preface to the Denkmaler deutscher Tonkunst, the musicologist Riemann cited the "Mannheim school" as an important group that helped define a symphonic style. Most notable among this group were Stamitz, Richter, and Cannabich. These preclassicists were key figures who laid the groundwork for the major Viennese composers who followed.
During the latter part of the 18th century, Haydn and Mozart defined the classical symphonic ideal. Haydn’s resources centered around the strings, and beginning in the early 1770s the harpsichord continuo was no longer included. Haydn consciously wrote with the limitations of the natural horns in mind and frequently added a pair of natural trumpets, called "clarini." His woodwinds consisted of a pair of oboes, to which clarinets and flutes were gradually added. The bassoon parts became independent from those of other bass instruments. A pair of small timpani tuned to the tonic and dominant rounded out Haydn’s orchestra. With a few notable exceptions, such as the contra bassoon part in The Creation, Haydn’s style was conservative, with understated use of color.
Mozart wrote for much the same combination of instruments, but with more interesting techniques. One combination he often used was the flute and bassoon doubled two octaves apart with oboe or clarinet at a sixth or third below the flute. His string writing was more adventurous than that of Haydn, with the possible exception of Haydn’s late masses. He utilized the clarinet in his Symphony No. 23 and frequently in chamber scores, but it did not have a clearly defined role in the classical orchestra. Trombones were not commonly used in the orchestra, except in sacred choral works, where they doubled alto, tenor, and bass vocal parts. Mozart also used them in his operas, as did Haydn in the Creation. The harp was almost never employed in the orchestra, and little percussion other than timpani was used.
During the late 18th century new instruments found their way into the opera pit, where more expressive, dramatic music was required. Gluck was an early pioneer of orchestral devices, utilizing the piccolo, contra bassoon, clarinet, trombone, English horn, and harp. A good example of his advanced style is Iphigenie en Tauride, composed in 1779.
Beethoven wrote his first six symphonies between 1799 and 1808, adding the seventh and eighth by 1812 and the ninth in 1824. These works remain monuments to which all symphonies before and after have been compared.
Beethoven used a standard classical orchestra in the first two symphonies. In the seven symphonies that followed he gave the strings five distinct parts and used them in divisi fashion. His third, sixth, and ninth symphonies incorporated the piccolo, clarinet, and bassoon in its upper range. The Eroica was a major step forward in Beethoven’s orchestral style. All through his output Beethoven wrote demanding parts for natural horns, and never used valved instruments, English horns, or bass clarinets. His Fifth Symphony marked the first inclusion of trombones in the orchestra. The programmatic characterizations in the Sixth Symphony were unique, and the massive vocal and instrumental forces in the Ninth Symphony foreshadowed later romantic tendencies.
Beethoven’s contemporary, Schubert, was a competent yet modest orchestrator. His use of trombones in the second movement of the Unfinished Symphony was unusual at the time. Mendelssohn wrote with sensitivity for instruments, and the scherzo from his Midsummer Night’s Dream shows delicate control of woodwind timbres. Schumann’s scoring was very dense and full, and it worked well with the forces he had at his disposal.
Carl Maria von Weber showed great expressive capacity with instruments in his Overture to Der Freischutz, composed in 1820. He was a true revolutionary who standardized the use of four horns, two trumpets, and three trombones. Giacomo Meyerbeer also introduced new instruments in a striking and unusual fashion. He is credited with the first bass clarinet solo, as well as use of the English horn and harp.
Berlioz was a major contributor to the field and a strong romantic influence for whom orchestration was both the means and the end. His Treatise on Instrumentation was the first comprehensive work on the subject. His brass sections competed on an even footing with the woodwinds and strings. Even with the tuba, which he was among the first to include in the ensemble, his brass pianissimo was a trademark. The Symphonie Fantastique is a landmark example of ways in which instrumental colors can be cast.
The middle period romantics made several adjustments to the orchestra. The string sound developed with the advent of the concave Tourte bow, expanding in size to balance with increasing numbers of winds, with independent parts for each instrument and special effects. Composers at this time called for more woodwinds, added the piccolo, but still did not regularly employ the English horn or contra bassoon. They made use of the improved valved brass but were not in the habit of adding the tuba. The typical number of timpani grew to three, and more use was made of the bass drum, cymbals, triangle, and harp. Curiously, the convention of ordering the score by choirs was not consistently practiced by all composers in the middle romantic period.
The symphony orchestra continued to grow in many ways through the late nineteenth century. The size of string sections expanded as the numbers of brass, woodwinds, and percussion increased. Sixty-five string players was a common number in a late romantic symphony. The four families of woodwinds were represented by three or four players each, with English horn, bass clarinet, and contra bassoon consistently present. Several French composers added the alto saxophone on occasion. In the brass section more than four horns were often required, along with three trumpets, three trombones, and at least one tuba. Much new ground was broken in the use of percussion, with bells, cymbals, gongs, tambourine, xylophone, celesta, two harps, and four timpani incorporated. There were many innovators among late romantic orchestrators.
The Russians were original in their tendency to preserve individual colors. Among the most adept and creative, Tchaikovsky used a traditional ensemble, without bass clarinet or contra bassoon, but added percussion. The distinction between primary and secondary material was always clear, and scoring decisions seemed inevitably based on the musical idea. Rimsky-Korsakov was a master at exploiting unusual colors and very influential in this regard. His book, Principles of Orchestration, which was an important contribution to the field, contains many examples from his music.
Among the Germans, Wagner was the most imposing figure in this arena. His scoring for strings was extremely demanding, and he consistently mixed choirs of different types of instruments, unlike the Russians. Well known for excesses in all dimensions, Wagner is credited with the notation for the stopped (+) horn technique. Mahler’s economical yet dramatic style stood in contrast. Among the most explicit orchestrators regarding notation, Mahler wrote music that was also very different from Bruckner’s, whose method was to use antiphonal choirs and score thickly. Brahms was not an innovative orchestrator, but his use of the ensemble suited his musical intent perfectly. His propensity for dense inner voices is inextricable from his compositional style. In general, Liszt patterned his orchestral style after Wagner’s.
The French were original, scored cleanly, and avoided excess, traits shared by Saint-Saens, Bizet, and Chabrier. Less fluent in this style was Franck, who had more in common with Bruckner. This may be due to the fact that they were both organists. In Italy, opera reigned over instrumental music through the later romantic period. Verdi was a competent orchestrator who used the ensemble as an accompanist. Puccini exhibited complete control over the instruments and employed pitched percussion in an original manner. The Czech composer Dvorák is notable for clean, original scoring procedures that characteristically present the folk elements in his music. Sibelius, a composer from Finland who was unique in his extensive use of the low register for all instruments, deserves mention here also.
The master technician of the period was Richard Strauss. In his tone poems he made virtuosic demands on every instrument, sought extravagant colors, and was especially concerned with woodwind timbres and techniques. His music is extremely dramatic, with impassioned moods shifting as does the plot in a theatrical performance. In that instruments represent characters in poems or folktales, Strauss set an example for film scorers of the 20th century.