Why is it hard to whistle with a dry mouth?

[Ken Fabian]

I whistle sometimes - a bit of bluesy stuff mostly, sometimes with roughly played guitar, sometimes by itself. I haven't found a good answer to why it is more difficult to whistle when my mouth and lips are dry. I've read claims it is because the mouth shape is easier to achieve with a lubricated mouth but was not convinced; I've seen harmonica players dip their instruments in a glass of water and recall school sports where the teacher/umpire dipped sports whistles in water like that ( to get more volume I thought), so I think it not just about the human mouth. I speculate that the wet film both smooths the texture of mouth surfaces and a wet surface reflects sound waves better - but does anyone have something more than speculation?

[Enthalpy]

I've had somewhat similar thoughts but not for whistling. I need much more time thinking at it, and the physical model and maths aren't trivial.

If someone knows an answer, I'd be interested too!

[koti]

Your lip skin is less melleable when its dry.

[Phi for All]

The embouchure for whistling is much the same as for blowing into a brass or woodwind instrument's mouthpiece. Licking the lips is the prelude to playing through those, and I think it's to seal the lip creases that happen when you blow, so all the air is used to produce the desired note.

[Ken Fabian]

4 hours ago, Enthalpy said:

I've had somewhat similar thoughts but not for whistling. I need much more time thinking at it, and the physical model and maths aren't trivial.

If someone knows an answer, I'd be interested too!

 

Brass and woodwind players talk about their instrument playing better after being warmed up by the breath, but it also adds condensation inside the instruments, ie wetting the inside surfaces. Related perhaps?

Koti, Phi for All,  those could be contributing factors but it is such a distinct difference that I doubt they are the main reason -  I don't think my mouth shape is a lot different dry to wet but perhaps tiny changes due to stiffer skin or lip creases may be enough. Would it make much difference in airflow for brass/woodwind players? The seal between lips and mouthpiece should be good and tight either way although for brass the lips touch each other in "blowing raspberries" style and being dry would affect that. Recollecting vaguely my childhood encounters with a soprano cornet, playing with a dry mouth could give me sore lips but I'm not sure I was discerning enough to tell if the sound quality was much affected.

[hypervalent_iodine]

40 minutes ago, Ken Fabian said:

 

Brass and woodwind players talk about their instrument playing better after being warmed up by the breath, but it also adds condensation inside the instruments, ie wetting the inside surfaces. Related perhaps?

Koti, Phi for All,  those could be contributing factors but it is such a distinct difference that I doubt they are the main reason -  I don't think my mouth shape is a lot different dry to wet but perhaps tiny changes due to stiffer skin or lip creases may be enough. Would it make much difference in airflow for brass/woodwind players? The seal between lips and mouthpiece should be good and tight either way although for brass the lips touch each other in "blowing raspberries" style and being dry would affect that. Recollecting vaguely my childhood encounters with a soprano cornet, playing with a dry mouth could give me sore lips but I'm not sure I was discerning enough to tell if the sound quality was much affected.

 

The seal formed for dry vs wet is quite different I think. For brass, another factor is that have your lips lubricated allows you to move your mouth around the mouthpiece easier, which is crucial for several reasons such as creating different sounds / intonations, and hitting higher and lower notes. Couldn’t say if it’s the same for woodwind, but I’ve played brass most of my life.

[Phi for All]

1 hour ago, Ken Fabian said:

Koti, Phi for All,  those could be contributing factors but it is such a distinct difference that I doubt they are the main reason -  I don't think my mouth shape is a lot different dry to wet but perhaps tiny changes due to stiffer skin or lip creases may be enough. 

The moisture doesn't change the shape of the mouth, but if you look at the way your lips wrinkle when you whistle, you can see how making them moist would seal the small crevices and increase the amount of air available for the embouchure. A liquid gasket, if you will, that makes the lips more flexible as it seals the gaps.

The moisture also keeps your lips from sticking to your teeth, but that's not as important in whistling as it is in speaking or singing.

[Enthalpy]

On 1/6/2019 at 4:06 AM, Ken Fabian said:

Brass and woodwind players talk about their instrument playing better after being warmed up by the breath, but it also adds condensation inside the instruments, ie wetting the inside surfaces. Related perhaps?

Yes, that's exactly what I was thinking at. I want for years to think and model that, have some ideas, but it's damn difficult. I had even imagined that "whistling" was a cover-up for the more important theme of wind instruments, figure that.

Having tried all the symphonic woodwinds and played several of them, I confirm that warming the instrument up is vital. More important for the more sensitive instruments, that is, the flute.

Whether is results from the temperature or the humidity? Present theories, with which I'm not pleased, claim that the temperature gradient down the air column must match the one for which the instrument was optimized. That would then matter for the alignment of the harmonics: a gradient different from the one used during optimization would detune the harmonics and make emission more difficult. But of tiny is the difference of frequency shift between fundamental and harmonics in a nearly cylindrical instrument? I doubt.

I also fear that, being presently an armchair inventor, any model I'd propose may be radically wrong. It would be much healthier to experiment first: distinguish the temperature from the humidity, build an instrument with purposely misaligned harmonics, dry the tube often or cool it permanently, measure the Q-factor, and so on.

[Ken Fabian]

Enthalpy - I was just curious and had hoped you might be aware of an existing explanation; I didn't expect you to take on the problem as a personal project! Or that you would have an existing interest in a related question of the affects of moisture films on the inner surfaces of woodwind instruments. Thank you for your replies.

[Enthalpy]

I only have some ideas for an explanation. But what matters at a wind instrument: the temperature or the humidity? The effect of humidity is badly difficult to model, so it would be better to experiment first. If it's a matter of temperature profile, as most books addressing the question suppose, modelling the humidity makes no sense.

This needs a lab, and I have nothing but a computer where I am presently. I don't even have my instruments. I'd be excited at investigating that and more about musical acoustics, for instance at a university.