Question

I have two flutes, with just one hole.. they both have same length (about 18cm), which gives me a fundamental mode of roughly 470 hz.
But in one flute, with little energy (blowing) i can easily make higher modes audible, but in the other one, only if i blow hard enough do i generate higher modes
why is it? :O
i checked the one in which i can easily do it, has a little smaller diameter than the other.. does this have anything to do with it?

Answer 1

Here are the pics!

Answer 2

diameter has a effect in lengths with an increment of 0.3d so when calculating resonating frequency we add up 0.3d

Answer 3

forget about that.. that is end correction.. don't u get my question? :(
@Vincent-Lyon.Fr

Answer 4

Hi! I think it is linked to the way the wave is produced in any instrument.

Let's recap! In the case of a flute, a regular flow of low-pressure air, but relatively high velocity, breaks on a solid edge.
The induced turbulences create random pressure changes of different (but small) amplitudes and different frequencies.
As the mouthpiece is linked to a resonating tube, only the resonating frequencies 'survive' and are selected (by constructive interferences) in the tube.

Now, what can explain the difference between you flutes? To produce higher-order harmonics, you need a faster air-flow.
The air velocity is determined by the way you blow, but also by the shape of the canal through which you are blowing: let's say the output cross section area is small, then the velocity will be higher, and turbulences of higher frequencies will be produced.

The diameter of the tube may also interfere. The narrower the tube wrt its length, the easier it should be to produce higher harmonics (think of a trumpet, narrow and very long, that allows the player to produce harmonics of a full scale between 8th and 16th harm.).

If your flutes were not solid wood as they seem to be, one way of experimenting would be to swap the mouthpieces and the tubes, on to connect the mouthpieces to identical tubes and vice-versa.

I hope this helps ;-)
From looking at your pic, is seems that the mouthpieces are relatively different in sizes on your two instruments.

Answer 5

the mouth piece is an integral part of the entire flute.. so i can't swap them :P..

and yea now that kind of makes sense to me.
is there some sort of a general law that tells which harmonics get how much energy ?

Answer 6

No idea, but it's a bit like quantum physics. When you increase the energy input into an instrument, instead of amplifying the existing frequencies, you give the instrument access to more higher energy modes of vibrations, hence 'colouring' the tone of the instrument.

A soft-played and a loud-played instrument do not produce the same spectrum and can be recognised, even if you adapt the output volume of your stereo system.

Answer 7

yes yes.. i have observed that.. when i play the flute loudly i generate higher frequencies.. this has been solved for light.. this is what blackbody radiation spectrum is right? :D
so there must be a similar solution for sound also