Sources of variation in phonetograms.

Despite the growing popularity of the phonetogram or F0-SPL Profile in the United States and its continuing use in Europe, it is generally acknowledge that a wide range of results are obtained by different investigators using the technique. Nonuniformity of results calls into question the basic validity of the method as a descriptor of vocal function limits. This article reviews some of the more common diversities in methods among investigators and suggests that variation of results in voice profiles may be as much an indication of nonstandardization of technique as in the inherent variability of subjects.