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 Curbing to Overdrive
In the video example below notice the ‘restrained’ half metallic character of the sound in Curbing changing to the loud, shout-like full metallic character of the sound in Overdrive.
The visual laryngeal appearance
The laryngeal gestures changes from 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 laryngeal gestures changes to Overdrive
In Overdrive the front and the back of the laryngeal opening approach each other, making the opening of the larynx much more narrowed and creating a more acute angle between the arytenoids and the aryepiglottic fold, and also an angle between the aryepiglottic fold and epiglottis. The cuneiforms are rolled in even more.
The visual laryngograph waveform appearance
The laryngograph waveform changes from Curbing
Also 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.
The laryngograph waveform changes to Overdrive
The laryngograph waveform in Overdrive shows a steep onset and a fairly long closure of the vocal folds and sometimes a roll off with a little knee. The steep onset indicates that the vocal folds are coming together very rapidly and stay together for longer, so they are more closed than open during the vibratory cycle, which corresponds nicely with the loud volume often used in Overdrive.
This video is a male singing on a sustained single note (C3, 260 Hz) on the vowel EH (as in ‘stay’) in Overdrive and on I (as in ‘sit’) in Curbing, alternating back and forth.
This video is a female singing on a sustained single note (B4, 480 Hz) on the vowel I (as in ‘sit’) in Curbing and on EH (as in ‘stay’) in Overdrive, 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.