Automatic Classification of Pitched Musical Instrument Sounds

This chapter discusses the problem of automatically identifying the musical instrument played in a given sound excerpt. Most of the research until now has been carried out using isolated sounds, but there is also an increasing amount of work dealing with instrument-labelling in more complex music signals, such as monotimbral phrases, duets, or even richer polyphonies. We first describe basic concepts related to acoustics, musical instruments, and perception, insofar as they are relevant for dealing, with the present problem. Then, we present a practical approach to this problem, with a special emphasis on methodological issues. Acoustic features, or, descriptors, as will be argued, are a keystone for the problem and therefore we devote a long section to some of the most useful ones, and we discuss strategies for selecting the best features when large sets of them are available. Several techniques for automatic classification, complementing those explained in Chapter 2, are described. Once the reader has been introduced to all the necessary tools, a review of the most relevant instrument classification systems is presented, including approaches that deal with continuous musical recordings. In the closing section, we summarize the main conclusions and topics for future research.