 The Clarinet BBoard
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Author: diz
Date: 2002-10-14 05:58
I read an article (Groves) about Saxophones and the reason they have such large tone holes. As this article was written for the rocket-scientist - it kind of went over my head.
Anyone with some good grasp of Readers Digesting this sort of technical information into "Plain English 101", please let me know?
thanks,
diz, Sydney
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Author: diz
Date: 2002-10-14 05:59
Opps - this is very off topic - Mark - please delete
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Author: ron b
Date: 2002-10-14 06:29
Seems related to clarinets in my opinion, Diz. I mean, I've wondered but never asked why some clarinets have larger/smaller holes than others. Saxes and clarinets have dozens of different size pads - graduated in .5 milimeters. At first glance a casual observer might assume all clarinets are the same; same length, color, bore diameter and pad sizes. When I first picked up a clarinet I supposed it was the same as all other clarinets. Now I know there are dozens and dozens of variations -- but I don't really know why. "They" have been manufacturing clarinets for ages... why haven't they figured out the ideal proportions by now?
Seems like a perfectly good question to me. Mainly, because I don't know the answer :|
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Author: Mark Pinner
Date: 2002-10-14 11:14
Sorry about the length of this response!
The main reasons for the size of the saxophone tone holes is for volume, intonation and bore size. Another possible explanation may also be in the fact that the saxophone is an adaption of the Ophicleide, a brass instrument with holes, and developed somewhat by trial and error. The pedigrees of the saxophone and clarinet are very different although they both use a single reed and players often double both. There is also the consideration that accoustically the the clarinet is a cylindrical stopped pipe which overblows the twelth and the sax is an open conical pipe overblowing the octave. Although on a sax the holes are large the pad sits relatively close to the tone hole making the hole effectively smaller and deliberatley interrupting the venting. Too far down and the horn will blow stuffy and flat, too high and the reverse happens. The bore of the sax is conical and has a wide flare over the length. If you look at a soprano sax it is the same nominal pitch as a clarinet and roughly, give or take a centimetre, is about the same length as a Bb clarinet. At the mouthpiece end of a soprano sax the bore starts at between about 7mm and 10mm and flairs out at the end of the horn to a bell 7cm to 10cm in other words it expands ten fold over its length. Discounting the size of the octave vents the upper most pads on a soprano sax ie. the high F# or G, high F, E speaker and the other palm keys take small pads in the vicinity of 6 to 8 mm which is small by clarinet standards. The lower pads ie. B and Bb are usually between 35mm and 40mm. These sizes are rough guides only. The bore shape of the clarinet is in theory cylindrical although some modern boehms push this envelope and any flare in the bore, again in theory, is only at the bell end for amplification. Again discounting the register vents the smallest pads on a Bb clarinet are generally around 8mm and the largest are up around 18 to 19mm. Considering the comparison of bore flare between the clarinet and the soprano the large pads on a clarinet are comparatively large. The bore of even poly cylindrical clarinets does not flare ten fold, five fold but much, much less and yet the pads increase from top to bottom 2 1/2 times. The sax flares roughly ten fold but the pads increase only 5 fold in the case of the soprano. The same comparison can be made between an Oboe and a Heckelphone. Both are conical but the Heckelphone flare is much larger and correspondingly so are the holes. Simple yet confusing!
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Author: Synonymous Botch
Date: 2002-10-14 12:00
Lemme see if I can get down-n dirty on this...
Smaller toneholes will admit less atmospheric pressure, allowing more of the pure tone to be emitted. Too small a hole will develope excess resistance and require more pressure from the player to speak at higher volume.
As MP alluded, there is a strict relationship between the cross-section of the pipe and the size of the tonehole (for a given note) that has some limited range of size (diameter) which may be adjusted by the designer.
I suppose the real problem in saxophone design is that the body is malleable and has some larger sympathetic resonances that can be excited by the player. When the upper toneholes are deformed, there may be some additional waveforms that propogate through the air column and interfere (destructively and constructively) with the note voiced at lower toneholes.
I don't have a firm grasp on Benade, but I think this is why older horns or those in poor adjustment warble on B and B-flat.
*******
The short version... lower notes have longer wavelengths. The distance across the tonehole must be large enough for a given wavelength to escape.
Think of a pipe-organ. How big are the vents on the little tubes?
How big are the corresponding slots on the 16 foot or 32 foot stops?
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Author: Ken Shaw
Date: 2002-10-14 19:27
When Boehm designed his new flute, he switched from the reverse conical bore of the older wood flute to a cylindrical bore (with a parabolic head joint) in silver. At the same time, according to his book, he used tone holes as large as possible, almost the size of the bore itself, so that the instrument would effectively end at the highest open tone hole. The new flute was much louder and more brilliant than the reverse-conical wood flutes and had a perfect chromatic scale. It was a big change in flute acoustics and took a fair amount of time to be accepted.
The large tone holes have been tried on a Boehm system oboe, but every description I've read says it was unplayable, or at least the sound was unacceptable.
I've never seen or heard of a clarinet with bore-sized tone holes. In fact, the only application I've seen is the "doughnut" hole for the left middle finger on the old Buffets with the left-hand fork Eb/Bb, and I've read that even this spoiled the sound.
I suspect that large tone holes won't work on clarinet because the sound reflects back from the bottom of the bore, to make the instrument act as a closed tube. If you take off the bell and play a low E or middle B, in addition to being out of tune, you get a blatty "bell" quality, which would sound on all notes if the holes were the size of the bore.
I'll post a query on the Early Clarinet board to see if there's any history.
Best regards.
Ken Shaw
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Author: Don Berger
Date: 2002-10-17 20:58
Very well discussed, Ken, I'll look for enlightenment, Happy Acoustics, Don
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