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Re: Shaper tips -- changing one aspect will cause what?

Author: JRC
Date: 2012-05-14 02:22

Let me see if I could contribute positively here but my comments are about relations to other characteristics in reeds, not just shape factor or the opening.

Oboe bore would have been simple conical shape if (1) the thickness of the oboe body was zero and (2) the input forcing function (reed) is a point source.

Unfortunately the thickness of the wood contributes to deviation from simple conical shape and replacing cut-off parts of the pointy conical portion with staple (tube) and the reed complicates the matter further.

So lets look at the tube and reed. Each oboe manufacturer offers their own tube and mandrel with specific conicity. That is a good starting point. It is their interpretation of completing their bore into a conical shape. Some use 46mm, 47mm, or even 48mm tube length. It seems to me that the player's preference in reed shape and length together with the tube would match the best with their oboe. Some find their reed does not work well in other instrument because different instrument may have different bore conicity.

The shape dimension influence two things; (1) volume of the air in the reed above the tube and (2) springiness of the reed that dictates how the reed would vibrate at different notes. The opening actually dictates the springiness of the reed much more than the volume of air being blown in. Larger opening reduces the controllablility of the pitch and sound more than the sound volume. It is a part of the resistance issue not the volume. A small opening with stiff (hard) cane gives you better controllability in general. Long scrape reeds works better with a bit more opening than that of the short scrape reeds because more scraping reduces the springiness of the reed. Stiffness (hardness) of cane and opening has direct relationship. Wide tip would allow easier production of low notes but stability of notes above 2nd octave g would suffer. The opposite is true in general.

The shape factor can be related to volume (as in size not loudness) issue; good match with the instrument would give consistent scale throughout the range. Bad match would give some inconsistency with pitch, stability of tone, ...etc. You could get the same effects by using different length tube.

The shape factor can be related to springiness of the reed issue that can be directly related to the opening of the reed, hardness of the cane, and type of scrape you use. It also directly affects easier/harder production of low and high notes but by overdoing it, it would start causing stability of pitch and tone problem. In another words, it is one of the knobs you could try out while you are searching for that "perfect reed" for your particular oboe.

So... just about every aspect of reed issues are inter-related. Shape is one of the knobs. I do not believe one should look at any one of these all by itself. This is a very hard subject to discuss in my opinion. Everyone have different habit of making and adjusting reeds and it is very easy to talk pass each other, and agreeing and disagreeing for no real common reference.

Post Edited (2012-05-14 02:27)

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