The Vocal Cord Movement -- 10,000 Miles

Krzysztof Izdebski of Pacific Voice and Speech Foundation talks about how far vocal cords travel in a single performance, if you could measure it out.

(Inside Science) -- "I can tell you anecdotally, but I actually measured this, that if you look at your thumb and your nail, the length of the vocal cord is typically the length of the nail on your thumb. And it’s kind of like a cone, ice cream cone, narrow at the beginning, wider at the end. These two structures can produce essentially an unlimited number of vibrations and pitches -- in a very developed voice, up to six octaves or more.

"So if you look at this from a, from a mathematical point of view -- so the vocal cord, let’s say, is 12, in a male 16 mm long, the vibrator portion. The widest portion at the end is, let’s say, 5 mm or 4 mm, if you make 100 hertz tone, ‘oooo,’ okay. So for one second, okay, that transitions to 100 repetitions.

"So let’s say you have 4 mm by 100 repetition, that’s 400 mm motion. In an operatic performance, the singer’s vocal cords move or run basically, well they stand in one place but the vibration can be translated into motion -- can you guess how many meters or yards or miles? 10,000 miles.

"So, so depending on stage time, so let’s say a singer sings for one hour, and [inaudible] range from A to A4, okay, so let’s say you have three octaves, or four octaves. So the vibration from, let’s say from 100 to 450, 144 hertz. Okay, so if you do 444 hertz, make it simple 500 hertz, and you repeat it over and over and over and over again. So for each 500, for one second of 500 hertz it’s 500 times 4 mm -- that’s 2,000 mm, that’s 20 cm, and if you go over so many minutes that becomes 10 kilometers, 11 kilometers, 10 miles.

"Just by singing. The motion. And it’s interesting. If you know how to do it, you get off, you go home and you’re not fatigued."