Here you see a highspeed videoclip of a male singer singing with distortion in Overdrive. The singers starts in Overdrive and then add and remove the distortion and rattle.
Notice the progressive narrowing of the supra glottis structure with Overdrive. The front and the back of the laryngeal opening approach each other, making the opening of the larynx more narrowed and the cuneiforms are rolled in even more than in Curbing.
Also notice the laryngeal gestures for distortion. Again you can see the additional narrowing with the distortion, and especially the false cords coming in and are vibrating, creating the distortion. Also there is medial- lateral constriction of the false folds and an anterior-posterior narrowing and the larynx is slightly raised.
The Rattle is produced by vibration of the cuneiforms or mucosa over the cartilages, either freely or against the epiglottis. Again there was evidence on endoscopy or from the Laryngograph of periodic vocal fold vibration.
Combined effects can be done safely.
Notice that the waveform of the vocal mode is maintained during the distortion and rattle. This indicates that the vibrations of the vocal folds are unhindered and unaffected by the distortion and rattle. So the vocal folds are vibrating freely under the distortion and rattle. This makes sense because the we know that the distortion and rattle is taking place higher in the vocal tract and not on the 1st level (the level of the vocal folds).
In all the examples where we can see the vocal folds, or look at the laryngograph trace, there seems to be a resonably regular pattern, and there didn’t appear to be any evidence of the effect (or any additional noises) being produced in the vocal fold level.
There was evidence on endoscopy or from the Laryngograph of periodic vocal fold vibration.