Throat whistling?

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"Italia's Got Talent, il fischio polifonico di Avio incanta i giudici: il tributo a Morricone vale il bis", La Repubblica 2/25/2021

Bob Ladd, who send the link, wrote:

It looks to me like he was producing the whistle aperture in his throat somehow and modifying the pitch by manipulating the size/shape of the oral cavity between the whistle and the outside world – I don't know if that makes any acoustic sense, but he's clearly not producing the whistle through a rounded aperture at his lips.

The mechanisms that Bob suggests make physical sense, though where in his vocal tract the performer generates the whistle is not clear. (Except that it's not the lips…) For background, see Christine Shadle, "Experiments on the acoustics of whistling", The Physics Teacher 1998:

The most common whistle is produced by blowing air out through tightly rounded lips, but it is possible to whistle while inhaling, or to form a constriction by pushing the tongue against the roof of the mouth. The amount of air flowing and the size of the constriction together help determine whether a whistle will actually sound. […]

Whistle-like sounds can be produced by mechanical systems with a number of different geometries. The basic requirements are threefold: there must be an obstruction in the path of a jet of air; the flowspeed (relative to the dimensions of the jet and any objects in its path) must be in an unstable range so that any perturbations in the smooth flow of the jet increase in size; and finally, there must be a feedback path by which specific frequencies of such perturbations are emphasized. […]

Sounds produced in this way are grouped into different classes by the type of feedback mechanism and geometrical configuration. Many wind instruments sound by means of an edge tone, where the obstruction is a reed (e.g., some organ pipes or any reed instrument) or an edge of the instrument (as in the flute, or at the mouth of a bottle). A teakettle, by contrast, has holes in two parallel plates. The first hole creates a high speed jet of air which produces a whistle when it is forced through the second hole, if the flowspeed and hole diameter cause the jet to be in the unstable range. Any whistle produced by this type of geometry is referred to as a hole tone. A tone known as Aeolian occurs when air flows past a cylinder, again for the right combination of flow velocity and cylinder diameter. The oscillations of the air in the wake of the cylinder apply forces in alternate directions to the cylinder. Aeolian tones can be heard when the wind blows through porch railings or pine tree branches; the same mechanism was at work in the Tacoma bridge disaster.

Although the Italian papers (and the YouTube posting) carry on about "polyphonic" whistling, in fact there's nothing polyphonic about the recording in question.  Here's a spectrographic display of one phrase:

Perhaps they're using polifonico/polyphonic to mean "melodic"?

The quality is striking enough that I'm tempted to suspect some kind of fakery — a playback device actually producing the tune, while the performer mimes appropriate mouth movements? I hope not. But maybe  Italia's Got Talent can engage Chris Shadle to investigate the mechanisms.

Update — I should mention that I'm particularly fond of the Morricone tune he plays, and of the movie it comes from.


  1. john burke said,

    February 27, 2021 @ 1:20 pm

    I think there are a couple of slight pitch inaccuracies (in the Morricone melody) starting about 1:00. If I'm right, that would suggest there's no fakery involved; it sounds highly accurate up to that point, so accuracy doesn't necessarily mean fake and inaccuracy suggests genuine.

  2. Y said,

    February 27, 2021 @ 2:16 pm

    Another video:
    The whistle is just as strong when his mouth is clearly closed (about 0:27–0:29).

    [(myl) Interesting — but technically, it seems possible that he's creating an edge tone in his larynx or thereabouts, with air flow maintained through the nasal passages when his lips are closed…]

  3. FM said,

    February 27, 2021 @ 2:54 pm

    I can produce a melodic whistle where the frication seems to be post-palatal/pre-velar. It's a lower pitch than my usual whistle, and rather breathy (my boyfriend walked in as I was trying it out and called it "spooky".) With practice I imagine I could do it without moving my lips. Definitely not with my mouth closed though!

  4. Trogluddite said,

    February 27, 2021 @ 4:27 pm

    MYL: "…it seems possible that he's creating an edge tone in his larynx…"
    Exactly that. If the video were clearer, I'm pretty sure you would see his Adam's apple bobbing up and down with pitch, as when modulating speech pitch. I suspect that the mouth movements are largely just showmanship.

    How do I know? Well; I have just discovered that I have missed out on an easy life of fame, monetising my rare talent on television! If only I had known as a child that being able to do this was so special! Mostly people think that it's incredibly annoying (I sometimes do it unintentionally, as an autistic "stim", as I do glossolallia – the physical feeling of doing it is strangely satisfying, which is possibly how/why I started doing it).

    As far as I can tell, I do it by just blowing air between my vocal folds, which are held more tightly closed than for normal speech (obviously I can't see this, but that's how it feels). Pitch modulation feels like it is done just as for speech, by modulating the tension in the vocal folds (my Adam's apple moves as when modulating speech). As Y correctly deduced, the mouth cavity plays no part in making the sound – I can do it just as well with my mouth closed (though Avio needs to project the sound into a microphone, which presumably he prefers not to have pointing up his nose!)

    I should add, however, that I don't have half the musical talent of Avio Focolari – I can hold a tune and modulate my vibrato moderately well, but I certainly don't have his pitch range or projection, nor the ability to simultaneously play the guitar!

    [(myl) VERY interesting! But as Chris Shadle wrote, "and finally, there must be a feedback path by which specific frequencies of such perturbations are emphasized." For example, the edge tone created by a flute player (or the base of an an organ pipe) requires interaction with the barrel of the instrument to create a specific pitch. So I'm guessing that both you and Avio Focolari are controlling the pitch (at least partly) by jaw, tongue, and lip movements. Again, we need Chris Shadle (or someone else with her talents) to investigate! ]

  5. Paolo said,

    February 27, 2021 @ 4:30 pm

    in the short interview before his performance, he said he had learned his whistling technique as a child, from an uncle

  6. Michael Watts said,

    February 27, 2021 @ 5:39 pm

    I whistle with my mouth open; the restriction of airflow happens in pretty much the same place that /s/ is articulated. This has impressed a number of people who think that whistling involves rounded lips. (I can also whistle that way, but it's more difficult.)

    The downside is that this method is quieter than normal pucker-based whistling. I've always wanted to learn the type of whistle done by sticking two fingers into your mouth; that one appears to be very loud. My whistle cannot be done with lips closed.

    I didn't learn it from anyone and don't really understand how a whistling technique could be learned or taught. (Demonstrated, sure, but taught?) I spent a while trying to whistle, and discovered that this worked.

  7. Y said,

    February 27, 2021 @ 5:57 pm

    Edge tones have significant harmonics, don't they? The fact that this is pretty much one pure frequency limits the possible mechanisms.

    Since closing the mouth does not affect the amplitude much, either the sound is mostly radiated through the nostrils even when the mout his open (which is hard to explain), or through the skin, as in humming or in the so-called voice bar.

  8. Trogluddite said,

    February 27, 2021 @ 6:01 pm

    Tongue movements may be involved – there certainly seems to be something going on right at the back of my mouth; again, feeling much like the modulations of speech. My jaw, lips, cheeks, and forward parts of my tongue are definitely not involved in producing the sound at all; I can do whatever I like with those bits without changing pitch – though of course, they can modulate amplitude and timbre to some extent (personally, I don't much like the turbulent "breathy" sound component when I let it out through my mouth).

    It's quite normal that I do it without any visual clue that it's me doing it. Not that I'd try to troll anyone, just that it takes no effort to conceal and I often begin doing it absent mindedly. Hence why I suspect that much of Avio's mouth movement is for show – it would look even more "fake" if he were stoney-faced, and it direct the listeners attention, much as a ventriloquist's dummy does.

    It's a shame that I'm way over here in Yorkshire, as you've piqued my own interest in knowing exactly how I do it (a fly on the wall would have seen some *very* strange behaviour while I've been confirming what I've written so far!) I've been doing it for over four decades without it ever occurring to me that it's any more strange than the fact that I *can't* whistle in the normal lips or lips-plus-fingers ways (I'm even more jealous of people who can click their fingers!)

  9. Y said,

    February 27, 2021 @ 6:14 pm

    Trogluddite, the larynx is attached to the hyoid bone, which in turn is attached to the tongue, so raising and lowering the larynx can involve various facial gestures. Some singers are notorious for it. It's not necessary but it can be more comfortable to let your mouth follow along with the larynx.
    When you make your whistling sound, is it a pure frequency, too, like Avio's?

  10. Trogluddite said,

    February 27, 2021 @ 6:35 pm

    @Y: "…is it a pure frequency, too, like Avio's"
    Yes; as far as I can tell from "inside my head" the timbre is the same, and I think pretty close to the sinusoid plus filtered noise that MYL's spectrogram suggests (I've been an amateur audio-DSP coder for a couple of decades, so that should be a fairly reliable judgement, but I'll rig up a mic and confirm later if I get a chance).

    Re: the facial gestures. Good point, I should have thought of that given the kind of gurning that I do when I'm playing bass guitar, never mind throat singing!

  11. David Morris said,

    February 28, 2021 @ 3:04 am

    Similar to Michael, I have a soft whistle around /s/ or /sh/, which sounds like a kettle whistle and is of no musical value. I just checked in the mirror, and my lips are usually quite wide (similar to /ɪ/).

  12. Joke Kalisvaart said,

    February 28, 2021 @ 1:49 pm

    My father can produce a very loud whistle trough the opening between his front teeth. Probably similar to David Morris 'kettle whistle'. I don't know if he can modulate the tone. He usually does it to atract attention over a long distance, because it's much louder than when he whistles through his lips.

    I can only whistle when I inhale. If I try it while exhaling I have little control over the tone and it costs me much more air so I can only produce a few tones before I have to breath in again. Inhaling, I can whistle longer lines and stay on tune.

  13. david said,

    February 28, 2021 @ 2:02 pm

    I can do it too. I remember learning in my childhood, perhaps from my mother, there were four ways to whistle: puckering, this way, with my fingers between my lips, and into my hands cupped together. I could do the first two easily, the fingers method slightly and the cupped hands not at all.

    I had forgotten this method until I read David Morriss’s comment. It’s like a whistling /s/ except my tongue is further back on the palate. Like Trogluddite I can basically control it and create melodies but nowhere near Avio’s skill. I suspect the microphone helps him a lot.

  14. Jerry Friedman said,

    February 28, 2021 @ 6:10 pm

    Why isn't this the same as other singers who have used the whistle register?

    Will Language Log take on Yma Súc?

  15. Jerry Friedman said,

    February 28, 2021 @ 6:11 pm


  16. Y said,

    February 28, 2021 @ 7:08 pm

    On a related note (sorry), this fellow has managed to produce a 5 kHz tone:

  17. Trogluddite said,

    February 28, 2021 @ 7:34 pm

    @Jerry Friedman
    Judging by the several vocal coaching videos which YouTube suggested to follow your link, the "whistle register" is exactly what I've been doing (though absent of the musical talent!). I've never used it as a singing register, nor has it ever occurred to me that I could; but the tutorials "reverse engineer" my serendipitous technique perfectly, and tally with my hunch that I use my vocal cords analogously to how one's lips are used when whistling conventionally (and apparently with a surprising connection to another LL favourite – vocal fry).

  18. david said,

    February 28, 2021 @ 9:50 pm

    The whistle register, which i first learned about from your comment, thanks, seems to be done with the mouth in an /a/ configuration rather than some sort of an /s/. To my ear, Avio doesn’t sound like the whistle register people in your link. I don’t know what’s happening at the vocal cords, perhaps there is a similarity there.

  19. Y said,

    March 1, 2021 @ 1:49 am

    Does the whistle register produce pure tones, or are there harmonics?

    [(myl) In the whistling analyzed in this post, there seems to be one harmonic:


  20. Jerry Friedman said,

    March 1, 2021 @ 10:31 am

    Trogluddite: Glad you found something of interest in my suggestion.

    david: Thanks for the comments. I'm way out of my depth, so I can't respond. But I withdraw the word "other" from my phrase "other singers who have used the whistle register". That was just sloppy writing. Even before you posted your sensible objections, I was aware that I didn't know whether Focolari was using the whistle register.

    By the way, if anyone wants to answer Y's question, Mado Robin's singing might not be the best place to look. At least a commenter at this YouTube video of her says she sang an extremely high note there without the whistle register.

  21. Stephen Hart said,

    March 1, 2021 @ 4:22 pm

    Wacky Whistle or Shepherd's whistle?

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