Over blowing an ocarina or xun.

[I.D.10-t]

Over blowing an ocarina or xun.
Does anyone know why this is not/cannot be done?

[Kypfer]

Not even sure what a xun is ... but with an ocarina, it's not that it can't be done, just that what comes out of the instrument when it's over-blown is very high-pitched and possibly not in any particular key ... literally eeek!!

It's all down to the physics of how an ocarina functions, specifically a Hemholtz Resonator, exactly akin to blowing across the top of a bottle. The instrument doesn't (normally) generate any high frequencies (harmonics), consequently there's nothing to over-blow for ... this is also the reason for the very "pure" tone of the ocarina, because each note is a single frequency.

[I.D.10-t]

Thanks tor the explanation and the additional information on the sound qualities produced. Do pan flutes fall under this type of resonance, or does the shape change things?

A Xun is basically a fipple free ocarina.

[Tim2723]

I believe the pan flute (especially any single pipe of the flute) is the kind of thing Hemholtz was talking about when he described a resonator. If there's any instrument more similar to blowing across an empty bottle, I don't know what it would be. An ocarina essentially changes its effective volume using holes and acts as a variable sized 'bottle'. A pan flute is essentially a bunch of fixed-volume 'bottles' all strung together. I think your description of a xun is accurate. It's really just an ocarina with a different kind of mouthpiece.

[Kypfer]

A pan flute is essentially a bunch of fixed-volume bottles

... nice, I'll remember that

I didn't comment earlier as I wasn't sure what a "pan flute" was ... I know them as "pan pipes"

[Tim2723]

They're synonyms.

[MTGuru]

It's all down to the physics of how an ocarina functions, specifically a Hemholtz Resonator

Good explanation, Kypfer. It's why the pop-sci explanation that "playing a flute is like blowing a bottle" makes me a bit crazy. I'm like, no, it's not. Well, the air reed excitation at the lip is basically similar, but what's happening in the body of the instrument is quite different.

It's seems odd that a Helmholz resonator has basically only one mode of excitation. But I guess it makes sense if you think about the mass and spring analogy.

The difference with monochords (strings) is interesting, too. Even though they're rich in harmonics, they can't be easily overdriven like wind columns. No matter how hard you pluck or bow, you can't push it past the fundamental without physically tapping an antinode.

[I.D.10-t]

Unlike nodes on a membrane? (Do drummers/bodhran players use the nodes?)

[Sigurthr]

There are certain types of ocarina which will overblow for additional range, but it isn't like on a flute or whistle - it doesn't follow a harmonic series. For example the Sol2 through Do1 italian "thin/long" style transverse ocarinas can achieve a range of two octaves in a singe chamber by use of overblown notes via experimental fingerings (where as normally the upper limit of range from any single chamber is that of one octave and a sixth). Also the higher (smaller) chambers of most asian double and triple ocarinas generally have at least one overblown accessible note. It is believed this ability comes about because the chamber's shape in those instances is very thin, long, and tube like often with a tuning hole at the far end, so when overblowing the pressure is great enough that it changes from a closed tube resonator to an open tube resonator.

I'm not sure if Xuns are incapable of flute-like overblowing; if you really try you can overblow a common beer bottle or glass jug and cause it to jump an octave. I can't manage to get the next partial higher, but I can definitely get the octave. I would assume you would be able to get the octave on a Xun as well, but do not have one to test it on.

I don't want to break any rules here, and I wish I knew if I were by saying this: you can always ask advanced ocarina questions over at the ocarina network. Lots of folks there will be glad to answer technical questions like this, there are even a few xun players and physicists who frequent the place. If I'm out of line in saying that, I apologize!

[I.D.10-t]

I guess part of it was that I was thinking of the overtones that a willow flute can produce when it has its end closed off.
(D-A-D-F#-A-C-D-E) It must be (?) the long 35:1 length to bore ratio that allows the instrument to produce overtones where as the more spherical a body is the less possible this becomes. I'll bet the same is true for open ended flutes.

[Kypfer]

I'll bet the same is true for open ended flutes

... I posted some relevant measurements regarding whistles somewhere else on this site viewtopic.php?f=1&t=81079&p=1012575&hil ... n#p1012575

Basically :

Long thin whistles - lots of harmonics, wide range of notes (potentially over two octaves) ... taken to extremes you'll only get harmonics, the tube will be too small diameter, relative to the length, to reliably produce a fundamental frequency.

Short fat whistles - very "clean and pure" notes, but few if any harmonics, so limited range.

A tapered bore, as used in a conventional recorder, introduces a whole bagfull of other parameters that you'll have to research for yourself, if you're interested!

[mutepointe]

would a xun have more of a flute sound than an ocarina?

[I.D.10-t]

would a xun have more of a flute sound than an ocarina?

I would guess that they would sound similar, but you would have more control over volume.

Some youtube clips
Playing Xun
Xun （Chinese Wind Instrument)
Happy Canada Day

[mutepointe]

Thanks for the clips. They sound like they have a softer mellower sound. That third clip is a must see. Woozie.