U84. 



VOICE. 



larynx falls, and the vocal tube is lengthened, 

 although during these changes the tones become 

 more acute. As soon as this has taken place, 

 the larynx again rises as the voice becomes 

 more acute. In a mezzo-soprano voice en- 

 dowed with a double falsetto, or third register 

 consisting of several tones of each register, 

 with the power of producing tones of the 

 same pitch either of the ordinary or the fal- 

 setto quality, we observed that the larynx fell 

 at the commencement of each register, and 

 that the thyro-arytenoid ligaments were twice 

 relaxed, but in a much smaller degree. These 

 observations have since been verified by many 

 musical persons. 



In order to explain the phenomena as con- 

 nected with the production of falsetto tones, 

 we must remember that at the highest note 

 of the primary register the crico-thyroid mus- 

 cles are contracted as much as possible in 

 closing the crico-thyroid chink, and therefore 

 that no further tension of the vocal cords can 

 take place. In this state of things, the thyro- 

 arytenoid muscles are at their maximum of 

 elongation, and their transverse section is a 

 minimum; consequently neither can a higher 

 note be produced by an extension of the liga- 

 ments, nor are these muscles in a condition to 

 affect the dimensions of the glottis; hence the 

 necessity of some alteration in the state of the 

 larynx in order to effect the scale of the fal- 

 setto, which is an octave above the ordinary 

 register, and to prevent the mere repetition of 

 the same series of sounds. This alteration 

 might be produced in two ways ; one of these 

 is a partial closing of the aperture of the glottis 

 caused by the action of the thyro-arytenoid 

 muscles when they have returned to their 

 ordinary condition, and are in a favourable 

 state to produce that effect under the influence 

 of the laryngeal nerves. For, let us suppose 

 the larynx to be in the same state as at the 

 commencement of the primary register, except 

 that the chink of the glottis is half c'osed ; 

 the consequence will be that as only half the 

 length of the ligaments can be made to vibrate, 

 the octave of the lowest note in that register 

 will result from the same tension which pro- 

 duced that note, and this will manifestly be 

 repeated in consecutive notes of the range of 

 the falsetto. This range is limited in general 

 to a few notes, owing probably to the chink 

 being soon completely closed by the stretching 

 of the vocal cords. It is also owing to this 

 partial closing of the glottis that a much less 

 quantity of air is required for the falsetto than 

 for the ordinary scale, which is proved by our 

 being able to sustain a given note in the fal- 

 setto to a much longer time than we can sus- 

 tain the corresponding note in the primary 

 register. The partial closing of the glottis was 

 observed by Majendie in his experiments on 

 the dog, and by Mayo in the human subject. 

 Another explanation was suggested by Gott- 

 fried Weber, namely, that the falsetto range 

 is caused by a nodal division of the vocal cords 

 producing harmonics of the fundamental notes, 

 by which means the glottis acquires the same 

 pitch as if it were half closed If we consider 



the glottis as a reed, it is evident that since 

 the number of vibrations must in this case be 

 the same for the same note as when we sup- 

 pose the ligaments to obey the laws of cords, 

 the axis of vibration or the breadth of the liga- 

 ment must be duly diminished, which may be 

 brought about by the rotation of the thyro- 

 arytenoid muscle on its axis. 



Having thus considered how the glottis may 

 act in the falsetto range, let us now examine 

 in what way the vocal tube contributes to its 

 formation. We have seen that this tube gra- 

 dually shortens during the ascent of the pri- 

 mary register, suddenly falls to its original 

 length when the falsetto commences, and again 

 diminishes during the secondary register. Now 

 it appears from Savart's experiments that, 

 notwithstanding the shortness of this tube, 

 the wave length of a column of air vibrating 

 within it is the same as that of a rigid pipe of 

 much greater length, and we have therefore 

 strong grounds for believing that the notes of 

 the primary register are reinforced in con- 

 sequence of the vibrations of the glottis being 

 always in unison with the fundamental pitch 

 of the walls of the tube ; hence in the falsetto, 

 when the vocal apparatus has resumed its 

 original condition, there will be less reinforce- 

 ment of the sound, since the parietes of the 

 vocal pipe are no longer in unison with the 

 glottis, but give its grave octaves. We have 

 found, by numerous experiments, that a flex- 

 ible disc will vibrate to almost any pitch, but 

 will reinforce the sound in a trifling degree 

 only, unless the pitch be in unison with its 

 fundamental note ; and on the same principle 

 we may suppose the intensity of the notes in 

 the second register to be diminished, and their 

 quality to be modified by the forced vibration 

 of the walls of the tube, while in the primary 

 all things concur in augmenting the effects 

 produced by the glottis. Miiller agrees with 

 Lehfeldt in opinion, that the falsetto notes are 

 produced by the vibrations of the inner por- 

 tion of the borders of the vocal ligaments, and 

 the variation of the pitch by their tension ; 

 and, although he does not mention by what 

 mechanism this is effected, he seems to attri- 

 bute it chiefly to the agency of the thyro- 

 arytenoid muscles. The author's explanation 

 is in many points coincident with that of 

 Miiller, but he has taken into account one or 

 two circumstances which appear to have 

 escaped Miiller's attention. The natural key 

 or pitch of the vocal organs may be found by 

 sounding the voice, without either elevating 

 or depressing the larynx. The grave octave 

 of that note will be the fundamental sound 

 of the vocal ligaments vibrating in their most 

 relaxed state, with the glottis entirely open. 

 Any tones of a graver pitch, produced by an 

 unusually relaxed state of the vocal cords, lose 

 both their quality and intensity, and cannot 

 be included in the compass natural to the 

 voice. According to the preceding principles, 

 the pitch of the voice being usually an octave, 

 or a fifth graver than the length of a column 

 of air within the vocal pipe, we see the cause 

 why a falsetto quality of sound cannot be 



