In the video example below notice the change of the character of the sound, the change in visual laryngeal appearance, and the change in visual laryngograph waveform appearance when the singer changes back and forth between the notes/modes.
The sound changes from Neutral without air to Curbing
In the video example below notice the non metallic and ‘clear’ character of the sound in Neutral without air, changing to the louder, and ‘restrained’ metallic character of the sound in Curbing.
The visual laryngeal appearance
The laryngeal gestures changes from Neutral without air
In Neutral without air you can see that there is no gap between the vocal folds. Be aware that when a rigid scope with stroboscopy is used it may sometimes look like there is a gap between the folds, but this is only visible posteriorly and at certain points in the vibratory cycle. To distinguish Neutral with air from Neutral without air first check to see if a gap can be identified (level 1). In Neutral without air and Neutral with air you can see that the posterior pharyngeal wall behind the larynx and hypopharynx is relaxed leaving the area open. The vocal folds can be seen easily as the false cords are retracted and the aryepiglottic folds are stretched more and tensed so they become thinner creating a funnel shape which is slightly steeper in Neutral without air than in Neutral with air.
The laryngeal gestures changes to Curbing
In Curbing the false folds approach each other slightly, covering some (the lateral aspect) of the vocal folds. The front and the back of the laryngeal opening approach each other, making the angle acute between the aryepiglottic folds and the lower part of the epiglottis. The opening of the larynx is more narrowed, creating an angle between the arytenoids and the aryepiglottic fold. The cuneiforms are also rolled in a bit.
The visual laryngograph waveform appearance
The laryngograph waveform changes from Neutral without air
The Neutral without air laryngograph waveform shows a shallower upward (closing) and downward (opening) curve compared to the sinusoidal waveform with occasional spike seen in Neutral with air. This corespond nicely with the louder volume often used in Neutral without air compared to Neutral with air. When compared to the metallic modes, the waveform is frequently bell shaped and symmetrical and the overall contact time is reduced which means that the gaps (when the vocal folds are apart) are shorter.
The laryngograph waveform changes to Curbing
Notice the Curbing laryngograph waveform. It shows a steep onset and a fairly long closure of the vocal folds with a roll off compared to Neutral. The steep onset indicates that the vocal folds are coming together rapidly and the wider shape indicates that the vocal folds stay together for longer, which corresponds nicely with the louder volume often used in Curbing.
This video is a male singing on a sustained single note (C3, 260 Hz) on the vowel I (as in sit) in Curbing and on EE (as in ‘see’) in Neutral without air, alternating back and forth.
This video is a female singing on a sustained single note (B4, 480 Hz) on the vowel EE (as in ‘see’) in Neutral without air and on I (as in ‘sit’) in Curbing, alternating back and forth.
These videos are from the endoscopy study performed by Julian McGlashan and Cathrine Sadolin at CVI in Copenhagen in June 2007. This study has not yet been presented.