Author: cjwright
Date: 2010-07-06 20:20
Wow, lot of information here.
I speak for my own scrape and my own experience, and lay no claim to my info/word being authoritative.
First of all, the bigger the bore of the staple, the sharper it is going to be. That is and acoustic law pretty much, and I find this to be true across the board. The reason I don't like chudnow staples is I find them riding high on the pitch for my scrape, despite them being 47mm long. Maybe with the right shape/gouge combination this would work, but currently for my setup it does not.
Secondly, the thickness of the wall, and the size of the oval directly effects how long I can tie a reed. Just for example, I use stevens thinwall. If I used Stevens thickwall, I have to tie shorter, because I need more surface area to close the sides with, so the throat needs to be wider. If I use thinwall, I can tie longer. Similarly, since Chudnow staples are larger in diameter, I have to tie shorter. the old Glotin and today's Rigotti are pretty darn small, so I can tie a lot longer.
Robin stated he gets dizzy spells from smaller diameter staples. I'm assuming he's talking about backpressure/airflow feeling different with a smaller bore. I can see where the diameter of the oval might effect the feeling of airflow on short scraped reeds since you don't put in windows like us Yankees. However, as an American scraping oboist, I can usually not tell any difference in airflow just by the staples diameter. Too many variables of the scrape on an American scraped reed can make it feel open or closed (the angle of the spine in relation to the rails, thickness in the middle of the tip, whether the windows are gouged out behind the heart or sloped in, etc.), and I manipulate these variables to gain the desired airflow (for me personally, more freeblowing but not without some resistance.)
The one major symptom of a staple being to closed for me is saggy side octave notes, which I commonly find with Rigotti staples. On the opposite spectrum, the only reason I find Chudnow staples difficult to work with is because they ride too high for me in pitch.
Jhoyla speaks against crimping staples and using wires instead. I think this strongly depends on your scraping, but for my scraping, I think wire would destroy my reeds. The wire creates new "node points" on the reed, which effect the vibrations and overtone sequences. The reason American oboists put wire on EH reeds (VERY GENTLY, as not to crimp the sides of the reed but rather just touch them) is not to keep the opening larger, but to create new nodes to bring the upper register to higher pitch. If you were to tighten the wire down hard enough to prop open the reed, you're cutting off vibrations from the blade downward and then the reed is is a goner.
I do crimp staples occasionally, but usually on older reeds when they're at their end and I just want one more use out of them. I do believe that crimping works better when you're first scraping the reed and it is newer, so the tie, shrinkage/warpage, and the reed hasn't settled completely so it's easier to manipulate. The location of where to crimp is also almost as critical as how much you do it. If you look at the shape of the piece of cane that is wrapped underneath the string, I generally crimp about 1/2 to 2/3 of the way down. Too high up doesn't work quite as well, and it's best to put the mandrel IN the staple before you begin crimping.
The tool I use more often came from David Weber for my birthday. Something he referred to as "reed proctology tool" which is much like a long narrow rod which I stick up the staple, and it changes the Y axis (up down) to be a hair wider, without dramatically effecting the X axis (side to side). I blogged about it a while back ago here. Unfortunately, David doesn't sell these commercially.
Finally, I believe the concept we are talking about regarding how big the opening of the staple is for maximum airflow while effecting pitch placement blah blah blah is called venturi. Wiki describes Venturi as being about fluid, but at the bottom it also states an example is "The barrel of the modern-day clarinet, which uses a reverse taper to speed the air down the tube, enabling better tone, response and intonation".
Cooper
Blog, An Oboe In Paradise
Solo Oboe, Thailand Philharmonic Orchestra
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