7. Evaluation
Because their range is so large, conventional methods of evaluating ethnomusicological material cannot be covered by this study. However, it is worthwhile devoting some space to the subject of automated methods of evaluation which are becoming more and more feasible with the developments being made in the field of electronics. The most prominent of these methods are melography (melodic transcription) and sonography (acoustic analysis using a sonograph).
The melograph, which comes in many varied forms, gives a continuous transcription of a melody in diagrammatic form, showing the pitch and length of each note. Apart from the basic difficulty of converting this diagrammatic read-out back into a format in which it can be widely understood, it also presents other major obstacles which prevent its wider application. It requires, for instance, recordings having an excellent signal-to-noise ratio, which is not always available. It also registers interference as part of the signal, it records some notes as being an octave higher than they actually are and, finally, it cannot be used for polyphonic music. Before the automatic read-out can be interpreted, therefore, it requires close critical examination.
While machines for the automatic transcription of two or multi-part music have not yet passed the prototype stage, the sonograph is already being widely used. This device provides an analysis of frequency against time, albeit only in relatively short sections of music lasting no more than a few seconds, but it provides a precise graph of individual harmonics. It is eminently suitable for delineating acoustic phenomena and, although restricted by the fact that it is laborious to operate, it can at least be used, for short pieces, for transcribing polyphonic music. It needs to be remembered, of course, that converting its read-out into conventional musical notation is extremely complicated. The applications of the sonograph go well beyond musicology and it has become a standard piece of equipment in phonetic and bio-acoustic analysis.
Finally, mention should be made of the various digital analytical and synthetic processes which are now emerging and which are being developed in various research projects. These techniques will bring decisive advances in the automation of analysis, even within the next ten years. Besides frequently requiring huge financial outlays, these methods will need intensive practical research and continual critical analysis. Only when we are prepared to provide the means of meeting these conditions can a proper appraisal of these techniques be made. This would also be an opportune point at which to establish from the outset a broad, even inter-disciplinary base for co-operation. It is essential for the success of audio-analytical programmes to insist on high technical standards or at least a thorough documentation of whatever standards are in operation, if one is to avoid the risk of interpreting any imperfections which occur in a recording as part of the original signals.
