Author: huboboe
Date: 2013-02-14 04:16
I'm glad you are working with the Ledet book. It was an eye opener for me years ago when I saw how many variations there are on simple themes: the 'simple' scrape (that was called the French scrape when I was as student in the 50's) to the many different versions of the 'American' (or Philadelphia or Tabuteau) scrape.
It's funny that the example of scraping on the spine over the heart is better shown on Harold's reed, which is much more of the 'standard model' than Ralph's... My immediate take on that is that it is possible to find the sort of compromise that will produce the sound you are looking for, but unless you put the 30 years behind that particular reed style into play, it's better to follow a more obvious solution... (Stevens Hewitt says, "Follow the beaten path. You will not have as much company as you think.")
Too many teachers offer Solutions that work for them but may not in another context. I think every suggestion is worth looking at, but shouldn't be considered gospel. Try it. Does it work?
I can't help the engineering bent of my brain and the need to put stuff into the larger context of 'why does that help the model work?'. Here's the broad strokes of my concept of reeds:
Because each fingered note on the oboe (or any wind instrument) basically makes a new instrument (different bore length, different bore shape, different tiny details) the reed still needs to be able to produce the entire overtone spectrum for that pitch in the same proportions in order to produce an even timbre over the range of the instrument. In short, the reed needs to be a white noise generator so that the instrument can select the frequencies it is asking for. Anything that interferes with this makes a 'bad reed'.
The short, thin parts of the reed vibrate at the higher frequencies, the longer, thicker parts vibrate at the lower frequencies. If you prefer the bright, Hollinger type sound, then the simple scrape should work well. If you wish a 'darker', more complex sound, then the many variations of the 'American' scrape are one approach to that. (And I prefer cream in my coffee...)
In the 'American' scrape, the thin part, the tip, is balanced across the thick part, the back, across the blend. The back could never vibrate from blowing pressure - it's way too thick. The blend transfers energy to the thick back from the easy blowing tip, but at the same time it restrains the freely blowing tip from blowing too freely, producing the 'balanced' sound we (I) prefer.
If the blend is too abrupt it detaches the tip, which then just goes, "tweeeee". if the blend is too gradual, the reed, if it plays at all, is resistant, and lacking higher frequencies.
A reed dial indicator is useful here. If your proportions are close to Martin Schuring's examples (which I like because his numbers match up with what has worked for me just about exactly), then if your heart is between .50mm and .45mm and your tip is between .05 and .07mm on a 70mm reed with a 4mm tip, then you are in the ballpark.
The crow will tell you where to go next. If it's too tippy, what's the resistance like? If it blows too easily, clip the tip. If there is a lot of resistance, thin the back. Either way you are balancing the teeter-totter across the blend.
Or decide that the resistance is right but not enough brightness. Dust the blend to free the tip a bit. These are the reed to reed decisions.
It's my theory that the back is a single architectural unit, divided symmetrically across the spine. If you consider the cross section of a reed blade through the heart. The un-scraped cross section was a crescent moon shape. Now it has two flat planes scraped on the top curve of the crescent, giving a cross-sectional shape which is thicker at the rails, thinner at the center of the channels and thicker again at the spine. Each of these four channels (hopefully symmetrical) starts near the wrapping at the full thickness of the cane, gets thinner as the scrape deepens and, usually is a bit deeper behind the heart, coming back up to what we used to call the 'hump', the same area now called the heart.
Somewhere along these smooth transitions from thick to thin is a spot that will resonate with most of the low frequencies. Somewhere along the blend to the tip is a place which will resonate with the high frequencies. Ideally you will have the balance you are looking for. If not, the crow will tell you what is happening most easily. You need to free up the stuff that isn't. Or inhibit a too free tip by clipping it, but check the resistance first.
Anything else you do, like windows in the back, will free up some portion of the spectrum but usually at the expense of something else, so be aware of all the results of your experiments, not jut, "did it get easier...". And choppy knife cuts are a serious offender in this department, no matter John Mack's meat ax reed on page 135!
Sorry for the long winded reply, but you caused me to try to distill years of reed instruction into a single post. And my initial reluctance is because I'm reluctant to break the divider between my two vibrating channels, but maybe his heart is too thick to vibrate easily. We don't have enough information. But I really think the model with a symmetrical tip and blend to the back and a symmetrical back with two channels on either side of a spine is the best starting place.
Think I'll go drink a beer now...
Robert Hubbard
WestwindDoubleReed.com
1-888-579-6020
bob@westwinddoublereed.com
|
|
The Oboe BBoard
.jpg){kind=small}
