Revision of the Hornbostel-Sachs Classification of Musical Instruments by the MIMO Consortium

Co-funded by the European Union through the eContentplus programme


The MIMO (Musical Instrument Museums Online) project has created a single access point to digital content and information on the collections of musical instruments held in a consortium of European museums. Co-funded by the European Union through the eContentplus programme, the project has entailed the harvesting of the digital content of the museums’ collections databases, to be made available online through EUROPEANA, the portal to the digital resources of Europe's museums, libraries, archives and audio-visual collections. The MIMO project has also involved the revision of the Hornbostel Sachs classification of musical instruments, with the main aim of classifying instruments such those in the new Electrophones class 5, invented since the publication of the original scheme of 1914 by Erich M. von Hornbostel and Curt Sachs.[i] A number of scholars have at various times revised or extended the scheme. The MIMO consortium’s version is closely based on the revised version (classes 1-4) by Jeremy Montagu[ii] to whom the consortium owes a debt of gratitude for generously sharing with us with us all resources associated with it; we also thank him and the editors of Muzyka for permitting the reproduction of the classification and some of the introductory comments in his article. The classification has been revised by the MIMO working group for classification and thesauri, chaired by Margaret Birley (The Horniman Museum, London) with contributions from many different members. Especial thanks are due to Arnold Myers (University of Edinburgh) and to Saskia Willaert (Musical Instrument Museum, Brussels). This version of classification has been incorporated within the databases of a number of the museums in the MIMO project.

Many of the new categories that have been introduced for instruments in classes 1-4 derive from the work of Jeremy Montagu. One is the addition of ‘retreating reeds’, a term used by Francis Galpin[iii] to describe what are usually wood or cane aerophones of tubular form, with a proximal open end and a distal end formed by natural node that is split in half, or built in two halves that are closed with a binding. Air blown through the tube forces the two halves to open and close periodically, creating sound. Since the vibrating air is not confined within the tube, ‘retreating reeds’ fall within the free aerophones category. Montagu’s ‘Dilating reeds’ category, within wind instruments proper, is for reeds made ‘from stalks of plants such as rice with vertical slits in the sides. When blown from one end of the stalk, the slits dilate under the air pressure, opening and closing.’[iv] ‘Edgetone instruments that are not flutes’[v] include ‘double disks, with a central hole passing through both sides of the disk, that one places between the lips and the teeth. These are made from tinplate, bottle-tops, or fruit stones, and are sometimes called widgeon whistles or labial whistles, and one plays them by breathing in and out through the hole.’[vi]

Performance techniques in instruments unknown to the authors in 1914 have also given rise to new categories in the classification. ‘Concussion bells’ (111.143) were added by Montagu to the classification ‘after acquiring a pair of Nigerian double-bells that are struck concussively against each other’.[vii]

In the membranophones group, the MIMO consortium has expanded and renamed the kettledrums section to include vessel drums of all shapes in which the single membrane and body form an enclosed entity, and has introduced a new category of vase-shaped drums many of which are represented in the collections of the Royal Museum of Central Africa in Tervuren, Belgium, one of the partners in the project. Museums often have no information as to whether or not both heads of a double-membrane tubular drum are struck, and the new subdivisions have an inclusive category for drums with two membranes, one of which may or may not be played.

Since the classification deals with instruments world-wide, the MIMO consortium advocates changes to nomenclature in the aerophones section, with the use of the more neutral term ‘reedpipes’ for all wind instruments proper played with a reed as an alternative to ‘oboes’ and ‘clarinets’ which are closely associated with western orchestral instruments with specific bore-profiles. ‘Horns’ and ‘trumpets’ may similarly evoke European brasswind. In addition to replacing these terms with ‘labrosones’,[viii] thus reinforcing awareness of the fact that not all lip-vibrated instruments are made of brass, the MIMO consortium has also expanded the classification to deal with specific types of European brass instruments. There are numerous examples in European collections, and the existing Hornbostel-Sachs classification does not succeed in dividing them into classes which correspond to how the instruments are treated by makers, musicians, or composers. Arnold Myers has extended the Hornbostel-Sachs classes to more usefully divide brasswind. This is particularly difficult since one accepted species of instrument can merge into another without a clearly defined boundary. The principles of division are:

  1. chromatic capability provided by: tone-holes / slides / valves

This distinction is easily recognised by non-specialists.

B. Bore profile is: conical / intermediate / cylindrical

No instruments are perfectly conical or completely cylindrical, but these terms are widely used and have an intuitive meaning. There is no clear boundary between these profiles. However, most users will probably recognise the examples given and be able to apply the classification scheme.

C. Bore is: narrow / wide

Again, there is no clear boundary between these profiles, but most users will probably recognise the examples given.

D. Air column is: short (less than 2m) / long (more than 2m)

Clearly, small and large instruments are different species in most cases.

The air column length of valved instruments is in most cases the shortest possible provided by the valves. There are some anomalies and problems (such as distinguishing the larger valve trumpets from the small valve trombones) but the scheme does allow useful subdivision to be made.

The classification of Electrophones owes its coverage of the field to the scholarship of Maarten Quanten of the Musical Instrument Museum in Brussels, and his thesis (in the course of development) that categorises components of electrophones as a series of interchangeable modules. While his full classification reflects the use of electrophones in the sound workshop, in composition and in performance, the modified and abbreviated version devised for the MIMO project uses separate categories for instruments and modules, facilitating their allocation to different classes by non-specialists. An original aim of the MIMO project was to develop a ‘simplified version of Hornbostel Sachs classification’ and this section of the classification remains within this remit. We are grateful to Maarten Quanten for his work, also to Dr Tim Boon of the Science Museum in London and Professor Clive Greated of the University of Edinburgh for their advice on this section of the classification. Unmodified acoustic instruments with attached microphones or pickups are classed within groups 1-4, according to the primary source of acoustic or mechanical vibration. All other instruments that use materials generating acoustic sounds, mechanically-driven signal sources, electronically stored data or electronic circuitry and produce electrical signals that are passed to a loudspeaker to deliver sound fall within the Electrophones group (5). The main subdivisions of the electrophones group include those identified by Hugh Davies[ix] and other authors[x] as electroacoustic, electromechanical and electronic instruments.

In the Introduction to their classification, Sachs and Hornbostel identified ways of creating numerical codes for instruments such as bagpipes, which comprise more than one category, giving examples of ways in which the code might be reconfigured to highlight different aspects of a given instrument. Since the numerical codes must be used consistently within the databases of the different MIMO partners, in the practical application of Hornbostel Sachs numbers to multicategory instruments within this digital context none of the abbreviations suggested by Hornbostel and Sachs have been used, rather, the codes have been used in full, without colons or brackets. As a general principle, the numerical code for any suffix that applies (or suffixes that apply) to all the categories appears at the end of the series of numbers. Thus the full numerical code for the Highland bagpipe would appear as 422.112-7+422.22-62 Double-reed chanter, conical bore (-7 with fingerholes) + set of single-reed drones with cylindrical bore (-62) flexible air reservoir for all pipes.

[i] Erich M. von Hornbostel and Curt Sachs. ‘Systematik der Musikinstrumente. Ein Versuch‘. Zeitschrift für Ethnologie, xlvi 1914, pp.553-590. Translated by Anthony Baines and Klaus Wachsmann as ‘Classification of Musical Instruments’ Galpin Society Journal xiv, 1961, pp. 3-29

[ii]Jeremy Montagu. ‘It’s time to look at Hornbostel-Sachs again’. Muzyka i, 2009, pp.7-27

[iii] Francis W. Galpin. ‘The Whistles and Reed Instruments of the American Indians of the North-West Coast’. Proceedings of the Musical Association xxix, 1903, pp.127-129

[iv] Montagu, ibid, p.12

[v]Laurence Picken. Folk Musical Instruments of Turkey. London: Oxford University Press 1975, p.376

[vi] Montagu, ibid, p.12

[vii] Montagu, ibid, p.4

[viii] ‘Labrosone’ was coined as ‘a handy term for “lip-vibrated instrument' by Anthony Baines. Brass Instruments: their History and Development. London: Faber 1976, p.40

[ix] Hugh Davies. ‘Electronic Instruments’ and ‘Electrophones’. New Grove Dictionary of Musical Instruments ed. S. Sadie. London and New York: Macmillan 1984, i, pp.657-690, pp.694-695

[x] Three categories of ‘electrophonic’ instruments that are synonymous with these are identified by Francis W. Galpin in A Text-book of European Musical Instruments (London: Williams & Norgate, 1937), cited by Hugh Davies in ‘Electrophones’ in the New Grove Dictionary of Musical Instruments, pp.694-695. Davies’ article also summarises the work of authors in the field up to its publication date. More recently work in classifying electrophones has been undertaken by Michael B. Bakan, Wanda Bryant, Guangming Li, David Martinelli and Kathryn Vaughn.‘Demystifying and Classifying Electronic Music Instruments’. Selected Reports in Ethnomusicology viii,1990, pp. 37-64, and by Hugh Davies ‘Electrophone’ New Grove Dictionary of Music and Musicians, 2nd edition ed. S. Sadie. London and New York: Macmillan 2001, viii, p.110