Visual & waveform recognition on Neutral without air on 18 larynxes
On the following 8 male and 10 female stills images from the videos both the laryngeal gestures and the waveform in Neutral with air are seen. The stills are extracted from the videos from the endoscopy study performed by Julian McGlashan and Cathrine Sadolin at CVI in Copenhagen in June 2007. The stills are extracted from the videos in the manner previously described. (See Laryngeal recognition in Neutral without air).
When looking at these 18 stills certain patterns are seen in the laryngeal gestures and the laryngograph waveform within each mode.
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 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 Laryngeal gestures and the laryngograph waveforms are more to be seen as patterns of progression from mode to mode, rather than absolutes. The larynx, the laryngeal gestures and the waveforms often differ from singer to singer, some singers have really weird waveforms, but still the patterns often show similar features. The progressive change in the patterns can be used as a guideline on how to identify the modes for an individual singer.