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

The sound changes from Overdrive to Edge

In the video example below notice the loud, shout-like full metallic character of the sound in Overdrive changing to the loud, scream-like full metallic character of the sound in Edge.

The visual laryngeal appearance

The laryngeal gestures changes from 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 laryngeal gestures changes to Edge

In Edge the opening of the larynx is even more narrowed, and the cuneiforms are rolled in even more than in Overdrive. This makes it hard to see the vocal folds. The narrowing creates an even more acute angle between the arytenoids and the aryepiglottic fold and also an angle between the aryepiglottic fold and epiglottis. The piriform fossae and area between the back wall (posterior pharyngeal wall) and the larynx becomes very small and is often closed off altogether. The larynx is raised to a higher position (you can see that it gets closer to the camera). tween the aryepiglottic fold and epiglottis. The cuneiforms are rolled in even more.

The visual laryngograph waveform appearance

The laryngograph waveform changes from 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.

The laryngograph waveform changes to Edge

The Edge laryngograph waveform shows a steep onset and a quite long closure of the vocal folds with a gradual roll off. The steep onset indicates that the vocal folds are coming together very rapidly and stay together for longer, so they are closed much longer than they are open. This corresponds nicely with the loud volume often used in Edge.

This video is a male singing on a sustained single note (C3, 260 Hz) on the vowel EH (as in ‘stay’) in Edge and Overdrive, alternating back and forth.

This video is a female singing on a sustained single note (B4, 480 Hz) on the vowel EH (as in ‘stay’) in Overdrive and I (as in ‘sit’) in Edge, 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.