OF THE HUMAN VOICE. 66 



As we know, all our senses are finite, thus with sight it is 

 the same thing. If I whirl a ball attached to a string round 

 slowly you can perceive clearly both ball and string, and 

 moreover no perceptible sound is produced ; but if I 

 increase the momentum beyond a certain point both ball and 

 string become imperceptible and then sound is also produced. 



jrdly — Sounds of the same pitch may differ widely in their 

 Timbre or Quality (the Germans call it Tone Colour), thus 

 the same note on a violin and a violincello, a trombone or 

 a piccolo, differ materially in character, and even the same 

 note on the same instrument produced by two different 

 players is often very dissimilar in tone, this is due to the 

 form of the vibrations. 



Having now, I hope, arrived at a definite idea of what 

 sound is, I will endeavour to explain the means by which it is 

 produced in the human voice. To understand the mechanism 

 of the human voice, I must ask your attention to these 

 diagrams. The human voice may be roughly compared to 

 a wind instrument, in which air is forced between two vibrating 

 bodies, as for example, the reeds of the clarionet. To produce 

 voice we require a current of air (as from the lungs), a bellows 

 to force it between the vibrating bodies (as the muscles of the 

 chest) and vibrating bodies, capable of delicate adjustment 

 (as the vocal chords). 



The vocal chords, are properly speaking not chords at all, 

 but membranes with free edges like the split parchment of a 

 broken drumhead. These chords must be brought parallel 

 to produce sound, in ordinary breathing they are slightly 

 divergent, allowing the breath to pass noiselessly ; when we 

 speak they are brought very quickly together by the Posterior 

 Arytenoid muscle and rendered tense by the Cricothyroid. 

 The Thyro Arytenoid re-elevates the Thyroid and relaxes the 

 chords. The greater the degree of tension, the higher the 

 note. And vice versa. 



The difference of voice in men and women is produced by 

 the difference of length of the vocal chords, which are \ 

 longer in men than in women and boys The size also of the 

 bronchial tubes, and capacity of the chest also modify the sound 

 of the voice. The range of the voice, depends on the 

 difference of tension which we can give to the vocal chords, 

 and on the control we possess over the muscles which tense 



