Thursday, May 17, 2012

The Reed As a Miniature Instrument

The Bassoon Reed As a Little Instrument

My former teacher, K. David VanHoesen used to treat the reed like a miniature instrument.  He worked with us to find the point on the reed blade for lip placement that made each note on the bassoon most resonant.  There were different places for different registers.

He would encourage us to play pitches on the reed alone to develop this skill.  I still use this in my first lessons with a new student.  You should be able to get about an octave's range of pitches on the reed.  The position for the lowest note may be similar to what you use when playing low Bb on the bassoon, the highest for high D or E.  When playing scales on the bassoon a subtle use of this skill is helpful for tuning and finding resonance.

Let's think of the reed as a small musical instrument that can be tuned and adjusted for maximum benefit.

Here is a chart of the reed's vibrating frequencies:

Think about the size of the tip opening needed for a low Bb.

To produce a full sounding low Bb that is down to pitch, you need a very loose embouchure.  The tip opening during playing would look something like the photo above.  Notice that the whole tip is open and the reed blades only contact each other at the corners.  From center to sides, the reed is vibrating across its whole surface area.

For a note in the second octave (the notes above open F) lips, air speed and fingering combine to close the tip a bit, helping the reed and air column to select the first harmonic and not the fundamental.  Using the fingering alone (half hole or no whisper key) is not sufficient to produce the correct pitch.  Try using a very loose embouchure and slow air speed to play a C above the bass clef staff and you'll get the lower octave.

Anyway, the tip must be closed down a bit.  The smaller opening helps increase the speed of the air rushing into the reed, allowing the faster vibrating frequency needed for the first harmonic.

Notice that the sides and part of the edges of the tip are in contact with each other.  While in contact they do not vibrate. This is called damping.

You are in effect making the vibrating surface of the reed more narrow.  The reed will vibrate faster and select out the fundamental, choosing instead, the first harmonic when the player plays a note in the second octave (the notes just above open F).

String players do this by changing to a different string.  Each string is different in thickness and length.  Bassoonists "change strings" by selecting differing amounts of reed for vibration with their lips!

It is as though we need three or four different reeds to play on.  A large fat one for low notes, a medium one for middle register and a small narrow one for high notes.

Speaking of high notes, here's what a reed tip would look like while someone is playing a high note:

Much of the reed is deactivated with such a closed tip.  This allows the open part of the reed to vibrate faster, allowing the bassoon to choose a higher harmonic for ease in the high register.

Since bassoon cane vibrates both with and across the grain, I'm over-simplifying some of this argument. What I'm going to say next is true, but an even greater simplification.

Let's go back to the reed spectrum chart:

Not only can we make assumptions about the pitches a reed can emit with a particular size of tip opening.  We can also make assumptions about the tone quality of a particular reed based upon the shape of the tip opening.

Assuming that only parts of the reed blade that are open in the static phase can be made to vibrate we can deduce from observation where the lows, middle range and highs in a particular sound can be found.

I credit the late L. Hugh Cooper for imparting his knowledge of the acoustic properties of reeds for this information.  Cooper was Professor of Bassoon at the University of Michigan for over 50 years and taught a class in acoustics there as well.  I had the honor of working with him during a sabbatical from Michigan State University about 15 years ago.

It has been universally observed that certain tip openings impart certain tone qualities. Below are two extremes:

Most bassoon players can just look at these two shapes and start to feel lip muscles adjust to the openings!

In the first one, the sides are heavily dampened.  They are not vibrating.  This reed has a covered, dark sound.

In the second, the sides of the reed are open and available for vibration.  Hugh Cooper identified the buzz or edge in a bright reed's tone as coming from a preponderance of lows in the sound. He believed that these vibrations came when the areas near the corners were open and available for vibration.

From this we can deduce that that is where the lows in the reed's sound lie.  By the lows, I mean the resonance from the fundamental and first few harmonics.

Following the color photos of reed tip openings above, you can then discover where the mid range and highs in the sound lie on the reed. 

You can play a low Bb with a loose embouchure that allows all of the reed to vibrate.  You can also play it with a very tight embouchure.

What happens?  You will either get a very sharp and dark low Bb or the octave above that Bb will sound.  By adopting a tight embouchure you close the reed tip, selecting out the lows in the reed's tonal spectrum and allowing only the highs and mid range to vibrate.  This raises the pitch and/or cuts out the fundamental.

Thus, it must be the case that the highs in the sound (the upper partials in a particular tone) exist in the spine or middle of the bassoon reed blade, since that's the only area vibrating with a more closed tip.

That leaves the mid-range, which, by process of elimination is found in the channels or the section between the spine and the rails.

So the big question in all of this is:  How do you adjust a reed to enhance one or more of these parts of its tone?

This is where the artistry in bassoon reed making is found.  Adjusting for enhancement of the lows, mid-range or highs in a sound is like adjusting the controls on a playback system.  Perhaps another analogy for the bassoon reed would be a stereo system!

I'll need another post to elaborate on the topic of adjustment.


  1. I remember learning that Cooper taught that what a reed sounds like up close (ie, to the performer) and what it sounded like to the listener were totally different. Didn't he teach that at around 30 feet, the "buzz" disappeared and you were left with the middle, pleasing vibrations.

    He also was adamant that trying to create the "dark" sound too soon in a new reed led to prematurely collapsed reeds, which were inevitably sharp and unresponsive. Better rather, to start off with a bright, buzzy reed and let it calm down over time due to the hardening of the blades and other factors.

    I think Mr. Herzberg was after something similar when he advocated scraping for pitch and response rather than tone.

    I'm really enjoying this series of articles. I'll be really curious if you have any thoughts on the parallel vs wedge scrape debate. I've pretty much always made a parallel scrape reed with pretty thin blades, but I've been studying with a German teacher who plays on big, heavy reeds, but uses an immense amount of air to make them vibrate. He says it takes more work, but gives a rounder, more flexible sound than on a parallel scrape.


    1. Hi, Derek,

      As you'll see in a later post, I agree with Cooper's approach -- starting with a reed that is a little bright or rough in sound often yields a reed that has a good complement of highs, middle and low when mature.

      It's also important to reiterate that a reed should have a little roughness in the sound right around the player. In a concert hall this sound will have the proper beauty, focus and carrying power.

      Many of us have little opportunity to play in good acoustical spaces without other musicians around so it's tough for us to develop this sense about the reed. I used to sneak into recital halls, churches, etc. just to get the correct feel for how my sound was coming off. Now I'm spoiled to have regular access to Severance Hall. I wish everyone had this opportunity!

      It's easy to go overboard with the bright reed thing, however. Remember, times have changed and the majority of players (at least in the U.S.) don't prefer the once mainstream brighter sounds of Sherman Walt and other East Coast mid-century bassoonists. I would put Cooper in that category, by the way.

      Through any edge in the sound, you should always be able to hear a solid, focused core -- a definite pitch.

      I stick with the near parallel scrape. I posted my blade measurements in a previous blog. There two tapers to my blade -- 1.) a very gradual slight taper (almost parallel) from collar to about 3/8" from the tip and then 2.) a more drastic taper to the tip.

      I believe this is pretty common amongst most American reed makers.

      I don't believe in playing on heavy equipment -- reeds, bocals, bassoons. I think the results are counterproductive.

      I'll say more about this in a later blog.