ABSTRACTS OF TECHNICAL ARTICLES 549 



lack of suitable quantitative means for simply evaluating the various 

 voice factors. With the aid of recently developed acoustic instru- 

 ments, the authors have investigated physical characteristics of vocal 

 tones, including attack, quality, vibrato, and power as a function of 

 pitch. Measurements have been made and repeated on more than 

 fifty singers in various stages of development. On the basis of the 

 results, it is possible partially to evaluate and criticize a singer's 

 technical equipment, and determine by periodic tests whether the 

 voice is improving or deteriorating. 



Better singers were found to attack a tone more vigorously and 

 sustain it more uniformly, to possess a vibrato with a rate of about 

 six per second, and to excel in those phases of artistry dependent upon 

 proper control. They are also capable of producing relatively high 

 amounts of acoustic power over wider singing ranges, the power in- 

 creasing gradually with increasing pitch. Harmonic analyses, with 

 the intensity levels of individual partial tones each averaged over an 

 interval of about .5 second, have as yet failed to reveal consistent 

 differences between good and bad voices. 



