﻿292 On the Falsetto or Head-sounds of the Human Voice. 



communication to the explanation of the mode of formation of 

 head- sounds ? 



We must first admit that clear falsetto or head-notes are har- 

 monic sounds ; then we must consider how harmonic notes can 

 be produced by the laryngeal instrument. 



If the vocal cords be regarded in the same light as the vi- 

 brating "tongue" of a reed-instrument, their nodes* must be 

 parallel to their edges ; when the whole breadth of the cords 

 vibrates, the harmonics are not heard, and the sound emitted is 

 said to be from the chest ; but if the cords meet only on a por- 

 tion of their length, then the vibrating-power of the blast will be 

 entirely spent in distributing the vibrations in a longitudinal 

 direction to those portions of the cords which are kept apart. 

 Hence the edges only of the cords will vibrate; the vibrating- 

 body may then be regarded as a narrow strip of elastic mem- 

 brane included between the edge of the cords and one of the nodes 

 nearest and parallel to that edge. An harmonic note, or a head- 

 or falsetto sound, will be the result of these vibrations. Now this 

 head-sound may be clear, sharp, and well defined, or it may be 

 cracked and even painful to hear. This appears to me due to 

 the circumstance that the vocal apparatus, being reduced to a 

 narrow strip limited on one side by its edge and on the other 

 by a node, becomes a true vibrating cord with nodes in a longi- 

 tudinal direction. If the cords meet in such a way as to limit 

 the direct action of the blast to the distance between two of their 

 corresponding ends and two of their corresponding nodes, an 

 harmonic sound will be emitted. In fact there will then be a 

 combination of the two harmonics, viz. the one belonging to the 

 vocal cord considered as a membrane, the other to the cord con- 

 sidered as a true cord ; the result will be the emission of a fine, 

 clear, sharp head-note. 



But if the cords do not meet in such a way as to limit the 

 direct action of the blast, as stated above, then the sound pro- 

 duced will be the same as that obtained when the exact spot to 

 bring out the harmonic of a violoncello-cord, for instance, is 

 not detected at once, the shrieking disagreeable sound of the 

 instrument showing the performer's skill to be open to much 

 improvement. 



The act of singing at will head-notes equally results in the 

 emission of harmonic sounds ; but its mechanism is not quite 

 the same as in the former case. I could not satisfy myself, as 

 I should have wished, as to the muscular action which brought 

 about the shortening and tight approximation of the vocal cords 



* It is hardly necessary for me to observe that the "nodes " of a vibra- 

 ting-cord are the places on the cord which, when lightly pressed with a 

 finger, yield harmonic sounds. 



