Numbers lower than 100 = solo instruments
200 = duets
300 = trios
400 = quartets
continue in this pattern until 900 = nonets
1000 + = large ensembles
1500 + = vocal music
Call numbers for solo piano have some helpful rhythmic divisions:
M 28 - Marches
M 30 - Dances (general)
M 31 - Two-rhythm (polka, etc.)
M 32 - Three-rhythm (waltz, etc.)
Some call numbers for larger ensembles with dance designation:
M 1047 - Dances (general) for orchestra
M 1048 - Two-rhythm (polka, etc.) for orchestra
M 1049 - Three-rhythm (waltz, etc.) for orchestra
M 1147 - Dances (general) for string orchestra
M 1148 - Two-rhythm (polka, etc.) for string orchestra
M 1149 - Three-rhythm (waltz, etc.) for string orchestra
M 1247 - Marches for band (original compositions)
M 1247.9 - Dances (general) for band (original)
M 1248 - Two-rhythm (polka, etc.) for band (original)
M 1249 - Three-rhythm (waltz, etc.) for band (original)
M 1260 - Marches for band (arrangements)
M 1262 - Dances (general) for band (arrangements)
M 1264 - Two-rhythm (polka, etc.) for band (arrangements)
M 1266 - Three-rhythm (waltz, etc.) for band (arrangements)
M 1356 - Dance orchestra or ensemble
M 1356.2 - Lead sheets for dance orchestras
M 1450 - Folk dances with directions that include music, unspecified region
M 1627 - 1853 - Folk music by region (Dance music may be included)