Last night the National Symphony Orchestra played Carlos Chávez's Toccata for Percussion Instruments. This 1942 score calls for 2 snare drums, Indian drums, 2 tenor drums, bass drum, claves, maraca, 2 suspended cymbals, large and small gongs, chimes, glockenspiel, xylophone, and timpani, distributed among six players.
How does one determine the DDC number for this work? The first step is to determine if the work is 782 Vocal music or 784 Instruments and instrumental ensembles and their music. Since the work is all instrumental music, one goes to 784. There, the next step is to determine the number of instruments and the number of instruments per part. Because there are multiple instruments and only one part of the score for each instrument, the work is classed in 785 Ensembles with only one instrument per part.
The next step is to determine if there are two or more instrumental groups (785.2-785.5) or only one instrument group (785.6-785.9). The score is only for percussion instruments; thus, it is classed in 785.68 Percussion ensembles. One might worry that one has to determine which family had the most instruments, i.e., more idiophones or more drums. However, the first note at 785.6-785.9 Ensembles consisting of only one instrumental groups states that subdivisions are limited to individual kind of instrument, not family of instruments.
The final step is to indicate the size of the ensemble by adding notation 19 from the add table at 785.2-785.9 Specific kinds of ensembles and then notation from 785.1 Ensembles by size. Because ensembles by size usually refers to the number of instruments, one might think that you must do this calculation. However, the note at 785.1 indicates that size for percussion instruments refers to the number of players. This ensemble is a sextet (785.16), so you then add notation 6 from 785.16 to notation 19. Thus, the DDC number for this work is 785.68196 Percussion ensembles for six players.