While many academics have written articles and books proposing various systems of classification and/or criticizing systems proposed by others, and some documentation is available for specific non-Western systems as well, few scholars have produced comparative studies of instrument classification systems in general. Cross-cultural analysis of musical instrument classification is possible with all the major classical cultures: Arabic, Chinese, Indian, Greek and European, as well as Tibetan and Javanese. Thanks to long literary traditions in those cultures, one can get some sense of how these systems have developed over time, as well as an awareness of the cultural assumptions underlying each system. Many systems of classification have been proposed by modern Western academics, including Hornbostel and Sachs, Hood, Lysloff and Matson, or Elschek and Stockmann, but there are also systems from orality-based cultures, including Mandailing and Minangkabau (Sumatra), T'boli (Philippines), Dan and Kpelle (Ivory Coast and Liberia), 'Are'are (Solomon Islands), and other indigenous peoples. In some of the smaller societies, musical instrument classification systems are not conceived or taught in an explicit fashion, and so scholars need to learn to explore concepts of instruments as found within each culture, which in turn may imply a presumed underlying classification.
Cultural studies of classification, whether they deal with botany, social structures, cosmology, or musical instruments, are always fascinating as well as controversial. The question of how people choose to divide up and organize their world - which features they choose to treat as meaningful distinctions, and the implied relationships and non-relationships that lie behind those choices - provide a unique perspective on the human mind, and on social and material culture. Musical instrument classification systems both reflect and influence how people think about, compose and hear music. Concepts and classifications of instruments and ensembles are part of the webs of cultural knowledge. The process of classification is not just a one-dimensional activity resulting in the production of a tightly-structured, systematic data set. Rather, it is frequently a multi-level, and at times creative way of thinking and organizing knowledge about instruments and ensembles in ways that are consistent with socially influenced or structured ideas or belief systems in a particular time and place.
Classification systems for musical instruments take a wide variety of forms, and use a wide variety of criteria for making distinctions. Many systems use the physical features of how an instrument makes its sound. Thus, instruments with strings are distinguished from those with membranes, and so forth; and progressively more detailed differentiations can be made along these lines. Some cultures classify instruments based on the materials out which they are made, such as the Chinese system, which classifies instruments as being made of wood, stone, metal or other materials. Another common way to classify instruments is by playing technique: e.g., struck instruments are distinguished from blown instruments. Many systems categorize instruments based upon their musical function in important ensembles within the culture. Tunings available on the instruments may come into play as well. Equally important - and this is just as true in text-based cultures as in oral cultures - instruments may have cosmological or spiritual connections, social and hierarchical positions, or cultural/historical associations, all of which can function as part of their categorization.
An interesting area of inquiry is the matter of how Western academic systems have developed over the last century. A number of thought-provoking issues have been at play. As some scholars have pointed out, recent Western systems are not based on 'natural classifications' - they did not arise organically in a process of cultural development in conjunction with a body of instruments. Instead, they were imposed upon the existing data in an after-the-fact intellectual process, usually the work of an individual. By the late 19th century, museum collections in the colonial metropoles of Europe and America were filling with instruments from around the world. The new awareness of different cultures stretched traditional Western classifications to the breaking point, and researchers, museum curators, and musicologists began to see a need to create a more comprehensive system. They called for a universal system, free of predisposition to any particular culture, which would be open and expandable to accommodate any conceivable sort of instrument that might be found, perhaps not realizing that the need to hegemonize is itself a cultural outlook. To meet that grand expectation, a system would need to possess two qualities: 1) It would have to be logical, meaning that for each progressive step of subdivision a single criterion of differentiation must be found that can be applied consistently and unambiguously; and 2) it would have to be logically exhaustive, meaning that there must be no holes that could leave unforeseen types with no place in the system. Over the years since these issues first arose, it has proven remarkably difficult to meet these prescriptions. The ensuing efforts to remove presumed cultural biases from the suggested classifications have been an ongoing exercise in sociological thought. And the struggle to achieve logical consistency and exhaustiveness has been a fascinating intellectual exercise of a different sort - a meditation, in many ways, on the very nature of musical instruments, calling for extensive detailed knowledge of the subject, complemented by great insight, but also humbling in its expansiveness.
Comparative analysis of how different cultures classify musical instruments can assist critical thinking about the predominant inherited system in European-derived cultures, the primary division of instruments into winds, strings and percussion, with further subdivisions following. Some have expressed disdain for this system for its obvious lack of logic, since the criteria of distinction are inconsistent and not mutually exclusive. But at the same time, it does accurately represent a division of musical functions within the Western musical system itself, and also reflects how most people in Western civilization naturally hear symphonic music and to varying degrees other music as well. It reflects a certain hierarchical thought, too, in which sustaining winds and strings are elevated to the most important positions, while the undifferentiated sounds of percussion instruments are sent to the back of the orchestra. In all these ways, the Western classification system is true to its purpose, true to the body of music and cultural associations that it serves, and in that sense it is meaningful and appropriate, although in a limited way. However, the Western system is less useful when discussing non-Western music. In the end, perhaps abandoning efforts to create a universal and hegemonic Western-based system would open the field to varieties of explorations on how each culture categorizes and classifies its own instruments.
[This essay was used by J. Progler with his students in a course on World Music at Zayed University in Dubai during 2003 through 2006. Progler has taught ethnomusicology (among other subjects) in Dubai, New York and Japan. Some of his writings on music are available online, including an article on music ownership in the digital age, a research paper on perceptions and performances of jazz swing (PDF), a piece on 'musical stupidity' (PDF), and an essay on teaching and learning the kora in West Africa. He also led a live dialog on the art of sound in the world of Islam for IslamOnline, and his 2008 book Encountering Islam includes a chapter on ethnomusicology and the representation of Muslim music. Some of these are archived here.]