PURPOSE: A model of vocal formants.

DESCRIPTION: This short tube is closed on one end and has a sliding reed inside it, so when it is inverted the reed slides from one end to the other. (The open end is seen in the photograph at the center above, and the closed end is seen in the photograph at the right. As the air passes through the reed it vibrates, producing a fundamental frequency along with a large number of harmonics.

When the reed slides toward the closed end "B" (away from the open end "A"), the vibrating air column becomes longer, so the harmonics resonated by the tube become lower in frequency while the fundamental frequency remains nearly the same. As the reed slides toward the open end "A" (away from the closed end "B"), the vibrating air column becomes shorter, so the harmonics resonated by the tube become higher in frequency while the fundamental frequency remains nearly the same.

When the air column starts long and becomes shorter, the sound goes ooh.......ah. When the gizmo is inverted, as the tube becomes longer the sound changes in reverse, going ah......ooh!! Click your mouse on the photograph at the left above to see a demonstration.

Additional videos show properties of two vocal formant models:

Click for green model: demonstration and for green model: wave shape and spectrum

Click for red model: demonstration and for red model: wave shape and spectrum

SUGGESTIONS:

REFERENCES: (PIRA unknown.)

EQUIPMENT: Plastic tube with sliding vibrating reed.

SETUP TIME: None.