Saturday, May 19, 2012

The Reed From Inside Out

The Inside of the Reed - Making the Inside Shape of the Reed Consistent

"Aside from scientific problems , the actual construction of reeds demands such flair, intuition and dexterity that the public would, if it knew, never believe it."   
Jean-Marie Heinrich in "The Bassoon Reed"

Bassoon reed makers spend most of their time adjusting what they can see -- the outside of the reed -- and very little dealing with what they can't -- the inside.

I have often thought it would be fascinating to pour wax or some similar substance in the reed cavity, cut away the reed and observe the shape of the wax impression inside.  Through doing something like that we could gain a better understanding of what shape the interior of the reed should have for good reeds.

Perhaps someone has already done this. 

It seems, however, that most of us adjust this area indirectly. By doing things to the exterior, we affect the interior.  Exceptions would be gouge and reaming, but I would venture to say that most of us don't spend a lot of time thinking about this.  Louis Skinner and some of the old German reed makers would be the exceptions here.

I do believe it's important to foster uniformity when forming the reed.  In my system the blank is formed and dried on the same taper (my custom-made mandrel tips) so that the taper of the inside of the reed is constant for every reed.

I wrap the tube area with a rubber band so that uniform pressure is exerted on the tube during the forming and drying phases. This avoids any bulges or cave-ins that might occur when the tube is formed and as the stresses of forming are distributed throughout the blank during the drying process.

OK, then, let's talk about the drying process.  This is, in my opinion, an under-rated part of the reed making process.  Often there's pressure on our "reed factory" to move the assembly line along as quickly as possible and shorten this phase.

I try to leave my blanks to dry for a month if I can.  Recently, I took some off the rack that had been drying since December and made them into reeds.  My yield was higher than usual and I ended up with some good reeds!

What's happening here?  Norman Herzberg had a good analogy.  He compared the drying process to what happens when you roll up a piece of paper and put a rubber band around it.  If you remove the rubber band soon after, the paper reverts to its flat state.  However, if you leave the band on for several days, the paper -- after the band is removed -- retains its new, round shape.  The fibers in the paper have shifted to relax into the curve of the rolled up paper.

The same is true with the reed blank.  The longer it sits in "cocoon" stage drying out, the more stable it is when you wrap it, cut the tip and start working on it. Reeds seem to need at least two weeks of rest in this phase to settle.

Indeed, it's likely, if you dry it as long as I do, that the reed may actually spend more time drying as it does on your bocal!

In a finished reed, there are some countervailing forces in addition to the wires that keep it from collapsing, even though a majority of the cane has been scraped or cut away.

One of them is the natural curve of the tube from which the piece of cane came.  There's a reason we use cane from tubes that are between 24-26mm. in diameter.  Cane in this diameter range makes the best tip openings.

It's all about tip openings, folks!

A smaller diameter yields a tip opening that arches more, a larger diameter one that is flatter.

The cane has a kind of "memory" built into its fibers that lasts well into the playing stage.  This memory is still there in the forming and drying process and during scraping and wire adjustment.

Perhaps when a reed reacts badly to changes we try to make to it, sometimes it's because we are trying to make it do something that it wasn't cut out to do.


This brings me back to my first blog post in this series -- the one about Expensive Profilers.

My argument against some of these fancy machines is that, when set to nearly finished reed thickness (If you set them thicker, you may as well just be using a cheaper machine, since the precise patterns set in them are made irrelevant through thickening.) the result is often reeds with collapsing tips -- especially if you have a slightly wide shape like mine.

Using the argument I made above that cane has a kind of "shape" memory built into it from the field and the drying rack, when you profile out much of the cane on the sides of the reed you are left with few choices in the tonal spectrum.

Before going on, I'd like to source the information I'm using to put these thoughts together.  This comes from Jean-Marie Heinrich, one of the few people in the world who has intimate knowledge of the bassoon reed, botany, geometry and physics!  His article, The Bassoon Reed, was presented 35 years ago to the Groupe d'Acoustique Musical, translated into English and published in the Double Reed Magazine (I believe in 1979).

This is an essential article for all bassoon reed makers.  It covers many things never discussed in reed making lessons and fills in gaps of knowledge that most of us have about how a reed works. I highly recommend you seek it out.  It is not easy reading, but well worth the trouble.

Anyway, one of the things he discusses is tip openings:

"If we study an excellent reed, we know that the reason for success lies in the geometry of the tip opening."

He identifies the dark reed as having "a tip opening contour containing points of inflection".

I owe you a short explanation here.  Please look at my drawing below.  At the bottom you will see the shape of the tip of a dark reed.  The points of inflection are the points at which the curve changes from convex to concave and vice versa.  The changes make for a weaker reed and allow for more damping as parts of the reed tip collapse easily, others do not.

For the bright reed there are no points of inflection, just one continuous curve.  The continous curve makes a stronger reed, allowing for less damping.

The drawings represent a set of reed tip openings in a progression of processing done to a reed starting with profiling and ending with a finished reed.  After profiling. the tip is of uniform thickness throughout (first drawing).  Through scraping and tuning (the kind that adjusts for tone quality) the concave curve of the tip degenerates into a convex/concave/convex "S" curve when taken to the extreme.

The reed tips with this final configuration are always dark in tone quality and have a light sound (by light I mean mostly highs and very middle or little lows).

My wide shape exacerbates this tendency by yielding a wider tip (14.5mm) and widens the areas that are convex if scraping is taken to the extreme.

Some double barrel profilers are set to yield tips that approximate the bottom two drawings.  I believe this leaves the reed maker with few choices for a tonal palette. 

Over-profiling or scraping in the channels and rails of the blade work against the natural arch imparted to the cane since its inception in the ground and limit its vibrating capacity in these areas.

If some cane is left on in these areas when profiling, the reed maker has many more options for the tone color of the reed.  Yes, there's a bit more work involved, but I believe it's worth it.  I'd rather have the option of leaving more cane on in these areas to help fill out the tonal spectrum of a particular reed than to have that option taken away before I have a chance to decide.

There are some other reasons to avoid finishing the reed scrape by profiling.
  • I frequently play on new reeds that work well with a little thickness still on them.  I know that this will need to be removed later when the reed stiffens up or mellows, but taking that extra thickness away right away would kill the reed in some cases.  This is especially true with cane that is a bit soft.
  • Reeds that begin with more cane on in the rails and channels do have a bright tendency.  There are many ways to mute that brightness without killing the reed.  I prefer a reed that is a little "rough" sounding at first as opposed to one that always needs to be boosted.
  • Reeds that start out dark and muted rarely turn into good reeds. It's very tough to boost a reed's sound.
  • As the top and bottom examples in my crude drawing are extremes that no one would want to play on, the best conformation for a particular reed tip lies somewhere in between. I believe it's best to have the ability to customize the degeneration of the curve for each reed, allowing for its individual characteristics.
I've ended this series on profiling and reed "theory" for now.  I've already gotten a few comments on some of these posts.  I hope more will add their ideas and experiences.

If you have trouble finding the reed articles by Kopp or Heinrich, let me know. I hope you've found what I've had to say worthwhile and challenging!

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