Vocal creak and fry, exemplified
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There are several different sorts of things involved on the perceptual side of the phenomena that people call "vocal fry" and (less often but more appropriately) "vocal creak".
One perceptual issue is the auditory equivalent of the visual "flicker fusion threshold". If regular impulse-like oscillations in air pressure are fast enough, we hear them as a tone; as they get slower and slower, we can increasingly separate the individual pressure pulses as independent events. The threshold at which the pulses fuse into a tonal percept is called "auditory flutter fusion" or sometimes "auditory flicker fusion". The transition between separation and fusion is a gradual one, and in the boundary region, we can hear the pattern in both ways, sometimes as what is called a "creak" sound, because it sounds like the creaking of a sticky hinge.
The other issue is the perceptual effect of pressure oscillations that are irregular as well as relatively low in frequency. Large amounts of random local variation in period sound like the sound of frying food, as bubbles of steam randomly form and pop here and there.
Both creak and fry can happen in human speech vocal-cord oscillation. But what people generally call "vocal fry" is actually more often mostly "vocal creak".
As an illustration of the auditory flutter fusion phenomenon, here are simple buzz stimuli at steady pitches from 20 to 120 Hz:
| 120 Hz | |
| 110 Hz | |
| 100 Hz | |
| 90 Hz | |
| 80 Hz | |
| 70 Hz | |
| 60 Hz | |
| 50 Hz | |
| 40 Hz | |
| 30 Hz | |
| 20 Hz | |
| 10 Hz |
And to illustrate the "fry" effect, here are 50 Hz buzz sounds with various percentages of random pulse offset:
| 0% | |
| 2% | |
| 6% | |
| 12% | |
| 24% | |
| 35% |
Here's an example of a pitch fall from 120 Hz to 60 and then to 50, without any "fry" irregularity, but with the final low values that give the impression of creak.
And here is a smooth fall from 160 Hz to 120, with an abrupt period-doubling to 60 and then a continued fall to 50, but again without any "fry" action:
In my opinion, a lot of the speech that people call "vocal fry" is actually one of these last two cases. (Though genuine fry does occur.)
Related posts:
"REAPER", 2/8/2015
"Sarah Koenig", 2/5/2015
"You want fries with that?", 2/3/2015
"Freedom fries", 2/3/2015
"Real fry", 6/19/2014
"Vocal fry probably doesn't harm your career prospects", 6/7/2014
"New vocal fry culprit", 6/18/2014
"Biology, sex, culture, and pitch", 8/16/2013
"Sexy baby vocal virus", 8/15/2013
"More on 'vocal fry'", 12/18/2011
"Vocal fry: 'creeping in' or 'still here'?", 12/12/2011
Isaac said,
February 8, 2015 @ 7:26 am
Sounds like me after a few chili dogs
John Finkbiner said,
February 9, 2015 @ 10:10 am
For some reason the second to last sample that is "an example of a pitch fall from 120 Hz to 60 and then to 50" sounds to me like the pitch drops for about the first 3/4 and then rises at the end. Or at least it did the first dozen times I listened to it. Now it seems to descend and then hold steady at the bottom, which is what the text suggests is actually happening.
Is there a reason a level-off should sound like a rise?
[(myl) You have sharp ears, and I made a stupid mistake in the Matlab code that generated the sound, so that in fact the last bit of the contour rose from 50 to 60 Hz rather than falling from 60 to 50. Should be fixed now.]
Doctor Science said,
February 9, 2015 @ 11:31 pm
I would really appreciate a link to a video of actual humans speaking with creak and frey, so I can compare and contrast. I find the sound codes too abstract to convey what you're talking about.
[(myl) There are some audio examples here, here, or here.]
Doctor Science said,
February 9, 2015 @ 11:31 pm
I would really appreciate a link to a video of actual humans speaking with creak and fry, so I can compare and contrast. I find the sound codes too abstract to convey what you're talking about.
MattF said,
February 10, 2015 @ 11:30 am
If you want an example of someone who creaks and fries all the time try watching one of Vi Hart's YouTube videos. They're also very entertaining.