High-speed photography is the science of taking very fast pictures. It records fast-moving objects as a photographic images onto a storage medium, often digital. After recording, the stored images can be played back in slow-motion.
A normal motion picture is filmed and played back at 24 frames per second, while television uses 25-30 frames. High-speed film cameras can film up to a quarter of a million frames per second by running the film over a rotating prism or mirror instead of using a shutter, thus reducing the need for stopping and starting the film behind a shutter which would tear the film stock at such speeds. Using this technique one can stretch one second to more than ten minutes of playback time (super slow motion).
High-speed cameras are frequently used in science in order to characterize events which happen too fast for traditional film speeds, i.e. the vocal folds vibrations.
In December 2012 Julian McGlashan and Cathrine Sadolin performed an endoscopy/high speed study at CVI in Copenhagen. We recorded 9 singers using highspeed technology. Each singer was examined using an high-speed digital camera:
- Photron Fastcam MH4
– 512X256 resolution
– Captures 8s B&W footage
– 4G Internal memory, download via USB 3
- 300W Xenon light
- Rigid laryngoscope
- Simultaneous Acoustic and ELG recordings
Laryngograph electrodes were positioned over the thyroid cartilages and an omnidirectional microphone placed at distance from the singer which allowed recordings at all levels of loudness. Also the ELG and acoustic signals were captured and analysed with the Speech Studio (Laryngograph) software program.
The longest high speed recording we made lasted 3-4 seconds and it takes around 17 minutes to play back.
High speed of Ornamentation
Here you see a highspeed videoclip of a female singer singing ornamentation in Neutral.
You can see the progressive narrowing of the supra glottis structure with the modes Neutral. There is no gap between the vocal folds, and 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 so they become thinner creating a funnel shape which is slightly steep.
Notice also the movement from the vocal tract producing the grid, which is the foundation of the ornamentations. The grid makes it possible to achieve an even and equal rapid run of notes.