Fingering information for a Calmont keyless oboe?

[margaretmfleck]

You are right about the vent hole! See pictures below.

Overall, this oboe is surprisingly small, compared to a D flute. This is because the acoustics work in a different way for a closed tube not an open one. The tone holes are exceedingly small, especially for the upper hand. There is a lot of slanting and undercutting in the tone hole that vents F# in order to get it in a comfortable position. The last picture attempts to show this. However, despite its very small tone holes and narrow bore, its quite loud. If I could play better I'd be happy to post a sound sample, but I probably shouldn't inflict that upon you all!

The acoustic tube length is only very slightly shorter, since it's a cone not a cylinder (see http://newt.phys.unsw.edu.au/jw/pipes.html). However, you measure that acoustic tube length starting from (more or less) the end of the reed for the oboe and the embouchure hole for the flute, so the wood part of the instrument ends up a lot shorter. Also, the bore is conical so the bore (therefore the instrument) is very narrow towards the reed end. (More narrow than a piccolo, which means oboe sites have long instructions and a tool for when, not if, you get the swab stuck.)

[margaretmfleck]

All right, so what am I missing, here?

I was thinking of moving this to world/folk winds. But it doesn't really fit there either. So I haven't.

Can't see why not, but okay.

The reason I put it here in the first place is that it seems to be intended as an alternate for a flute (e.g. like the Breton subois) rather than for the roles/music that you'd play on a duduk or bombarde. Calmont seems to have also made bagpipes and flutes.

[paddler]

You are right about the vent hole! See pictures below.

Overall, this oboe is surprisingly small, compared to a D flute. This is because the acoustics work in a different way for a closed tube not an open one. The tone holes are exceedingly small, especially for the upper hand. There is a lot of slanting and undercutting in the tone hole that vents F# in order to get it in a comfortable position. The last picture attempts to show this. However, despite its very small tone holes and narrow bore, its quite loud. If I could play better I'd be happy to post a sound sample, but I probably shouldn't inflict that upon you all!

The acoustic tube length is only very slightly shorter, since it's a cone not a cylinder (see http://newt.phys.unsw.edu.au/jw/pipes.html). However, you measure that acoustic tube length starting from (more or less) the end of the reed for the oboe and the embouchure hole for the flute, so the wood part of the instrument ends up a lot shorter. Also, the bore is conical so the bore (therefore the instrument) is very narrow towards the reed end. (More narrow than a piccolo, which means oboe sites have long instructions and a tool for when, not if, you get the swab stuck.)

The key difference between an oboe and a flute is that acoustically an oboe behaves as a tube that is closed at one end, whereas a flute behaves as a tube that is open at both ends. A closed tube resonates at the same frequency as an open tube that is twice its length. Or stated another way, the standing wave inside the tube is a full wave-length in a closed tube, and only half a wave length in the open tube.

This basically means that an oboe can be much smaller than a flute of the same pitch. Both flutes and oboes can have conical bores, and in fact our Irish flutes do have conical bores like an oboe, just not as narrow. The effect of over-blowing a closed tube is also different than for an open tube. You can see a more precise explanation here.

The acoustic length of this oboe is roughly the distance from the reed to the vent hole on the side, not to the end of the tube, which is much smaller than for a D flute.

Nanohedron's question about the purpose of that bottom section is pertinent here. I had a similar question. Not so much why is it there at all, but why isn't it a bell shape like on other oboes. Anyhow, the acoustic length of the tube is not completely terminated by the vent hole, especially for higher harmonics. So the amount, and shape, of the tube below that has some effect on the tuning of them. Its for reasons like this that cross-fingering works on small-holed flutes.

[paddler]

I would expect that half-coving holes should work for some accidentals (like it works for some accidentals on flute).

One thing to bear in mind here is that the tone holes are much smaller on this oboe than on flutes. For example, on our keyless flutes we often complain about the difficulty of half-holing Eb because the tone hole that vents that note is often only 6 mm or so in diameter. Well, on this oboe the smallest tone hole is only 2.6 mm in diameter! This makes it basically impossible to half-cover. Some of the lower tone holes are larger, but still considerably smaller than on a flute. It seems to lend itself to cross fingering more than half-holing.

I have wondered if the difficulty in playing C# (with all tone holes open) was simply due to the fact that even a very slight shrinkage or blocking of a 2.6 mm tone hole would have a significant flattening effect on the note it vents. In this case, a very slight closing of that hole might cause it to produce a C natural rather than a C#. The small size of this tone hole is exacerbated further by the thickness of the wall at that point in the instrument, meaning that the chimney height for that hole is very high in addition to its diameter being very small. So, acoustically it is an extremely small hole. I've never seen anything even remotely like this before. Its surprising to me that it speaks at all, never mind as loudly as it does.

[awildman]

Perhaps it's just designed to play in D Mixy? I'm no history buff, but I seem to recall that many old bagpipes had a flattened 7th. Maybe I'm misremembering, but I seem to remember a good piper telling me about old uilleann or pastoral sets and the prevalence of D Mixy tunes. It is possible that there is a connection between certain bagpipes and your oboe, besides the obvious double-reed similarity.

[margaretmfleck]

The key difference between an oboe and a flute is that acoustically an oboe behaves as a tube that is closed at one end, whereas a flute behaves as a tube that is open at both ends. A closed tube resonates at the same frequency as an open tube that is twice its length. Or stated another way, the standing wave inside the tube is a full wave-length in a closed tube, and only half a wave length in the open tube.

This basically means that an oboe can be much smaller than a flute of the same pitch. Both flutes and oboes can have conical bores, and in fact our Irish flutes do have conical bores like an oboe, just not as narrow. The effect of over-blowing a closed tube is also different than for an open tube. You can see a more precise explanation here.

The acoustic length of this oboe is roughly the distance from the reed to the vent hole on the side, not to the end of the tube, which is much smaller than for a D flute.

Nanohedron's question about the purpose of that bottom section is pertinent here. I had a similar question. Not so much why is it there at all, but why isn't it a bell shape like on other oboes. Anyhow, the acoustic length of the tube is not completely terminated by the vent hole, especially for higher harmonics. So the amount, and shape, of the tube below that has some effect on the tuning of them. Its for reasons like this that cross-fingering works on small-holed flutes.

That Wikipedia reference, also the much better site by the musical acoustics folks at New South Wales, both state that a closed cylindrical instrument (e.g. a clarinet) plays at half the frequency of an open cylinder, but a conical one plays at the same frequency as an open cylinder. As you say, the whole thing is complicated by the fact that none of these instruments are quite the ideal shape. E.g. flutes are often tapered, but in the opposite direction from an oboe.

In any case, if you measure from the reed to the vent hole, it's 3" shorter than the first Irish flute that came to hand, 1" longer if you think the relevant measurement is to the end of the bore (not the vent). If it were acting like a half-closed cylinder (e.g. like a clarinet), it would be playing much lower (maybe around low F).

I think this doesn't have a bell because it's intended for indoor use. The similar instruments with bells (e.g. bombardes) tend to be very loud.

[margaretmfleck]

It's flanked by (and sort-of lined up with) cylindrical-bore Irish flutes in D and F. Top is a D flute from Casey Burns whose bore tapers in the opposite direction.

[awildman]

A UP chanter would be a good comparison, since it is D-pitched, existing/established, is, of course, a double reed instrument, and is conical. I bet you'll discover a lot more similarities with UP than with flute.

My chanter is approximately 17.5 inches from bell to reed tip. Or if it helps take the "foot" out of the picture, 12.25 inches from E sounding hole to reed tip. Mine has small holes compared to most chanters. Smallest is 1/8", largest is just shy of 1/4". Bell size is approx 13mm or 1/2".

I've dreamed for years about having a 'folk' oboe similar to UP chanter. Not too loud or piercing, and plays well in the standard keys. I'd be down to buy one. Especially if it used a standard reed, like bassoon or EH, for easy replacement. (You would need a larger reed to get the more mellow UP-type sound, I believe.)

[paddler]

You are right, the cone shaped bore does change things compared to a clarinet, and makes it longer than an equivalently pitched clarinet would be. But this oboe is still considerably smaller than an equivalently pitched flute. When I compare the sounding lengths to a D flute with a long foot, I see that the oboe measures 440 mm from the end of the reed to the center of the hole that vents D, whereas a D flute measures 520 mm. As your picture shows, this D oboe feels closer in size to an F flute than a D flute, at least in terms of the relative position of the holes that vent the notes. This is what I meant by the oboe being surprisingly small compared to a D flute.

Here is a pic compared to a D flute with a long foot. Here you can also see what I mean by the tone holes being small, and difficult to half-hole, especially for the left hand.

And here is a close-up showing that the oboe's vent hole for D aligns with the flute's vent hole for E, with the reed top and embouchure aligned.

[paddler]

A UP chanter would be a good comparison, since it is D-pitched, existing/established, is, of course, a double reed instrument, and is conical. I bet you'll discover a lot more similarities with UP than with flute.

My chanter is approximately 17.5 inches from bell to reed tip. Or if it helps take the "foot" out of the picture, 12.25 inches from E sounding hole to reed tip. Mine has small holes compared to most chanters. Smallest is 1/8", largest is just shy of 1/4". Bell size is approx 13mm or 1/2".

This oboe is just over 14.5 inches from the E sounding hole to reed tip. So, it is somewhat similar, but a bit bigger. Maybe the UP chanter has a slightly more cylindrical bore? I suspect that this oboe and a UP chanter both have a bore shape that is somewhere between that of a conventional oboe and a clarinet, but that they have differing degrees of conicity?

I've dreamed for years about having a 'folk' oboe similar to UP chanter. Not too loud or piercing, and plays well in the standard keys. I'd be down to buy one. Especially if it used a standard reed, like bassoon or EH, for easy replacement. (You would need a larger reed to get the more mellow UP-type sound, I believe.)

That would be nice! Maybe we can talk Casey into designing one? I also have a duduk, which is a simple system instrument with a very large double reed and a cylindrical bore. So its even smaller and relatively deeper pitched than this. It has a very nice mellow sound to it.

[awildman]

"This oboe is just over 14.5 inches from the E sounding hole to reed tip. So, it is somewhat similar, but a bit bigger. Maybe the UP chanter has a slightly more cylindrical bore? I suspect that this oboe and a UP chanter both have a bore shape that is somewhere between that of a conventional oboe and a clarinet, but that they have differing degrees of conicity?"

Maybe; I'm no expert. I propose you saw off the bottom of your oboe at the D and measure the bore so we can compare better.

In all seriousness, Just about anything will impact the volume of the vibrating air column, starting inside the reed. UP reeds have a lot of internal scraping compared to oboe, IIRC, thus increasing the internal volume. Surely the width of the reed and the length of the staple will also have an effect. Even something simple like depth and size of toneholes will change the internal volume. UP chanters have a complex bore - different reamers are used in its construction, so the air volume will be different than something with a straight taper. Longer oboe foot will change things for sure. And as I indicated earlier, the closed nature of a UP chanter adds an extra dimension.

Long story short, the internal volume of my chanter has to be greater than that of your oboe, regardless of the specifics.

"That would be nice! Maybe we can talk Casey into designing one? I also have a duduk, which is a simple system instrument with a very large double reed and a cylindrical bore. So its even smaller and relatively deeper pitched than this. It has a very nice mellow sound to it."

Yes please, but definitely conical so it overblows at the octave properly.

[paddler]

Yes please, but definitely conical so it overblows at the octave properly.

That is a good point. The duduk definitely does not over blow at the octave like this oboe does.

[awildman]

"Long story short, the internal volume of my chanter has to be greater than that of your oboe, regardless of the specifics."

Rather, that the bore has to generally be larger for a shorter instrument of the same pitch.

[an seanduine]

As a point of information. Most modern UP chanters are very close to 14.5 inches for a modern pitch 'D'. That is, from top of reed seat to bell. The slope of a UP chanter is intimately connected to it's overall pitch. Narrow bores run flat. The slope also is tied to the harmonics available. The narrow bores are also more disposed to 'shading' of pitches with alternate fingerings. We needn't drag in the effect of stopping the chanter. . .

Bob

[margaretmfleck]

I suspect that this oboe and a UP chanter both have a bore shape that is somewhere between that of a conventional oboe and a clarinet, but that they have differing degrees of conicity?

The oboe is more conical than it looks. For the Calmont one, the bore is 5/8" at the bottom end, but only 1/8" where it joins the reed. This is not obvious from the outside. The top end has thick wood and space for the cork (that seals the reed into place). So what you see of the top still looks fairly wide but the actual tube inside will only just fit a pipecleaner.

Margaret