Brains and Membranes

Bassoon Reed Making by Christopher Millard

Chapter 19 – CHIAROSCURO

Chiaroscuro

 Light & dark

Caravaggio and Corelli, one a painter, the other a tenor.  Both transcendent masters of the balance of light and shade.

Our Little Bassoonist has studied Caravaggio’s paintings, his human figures illuminated by shafts of light, the backgrounds indistinct, shadows balancing the highlights. She has listened to Corelli’s recordings, his spinto tenor lyrical yet powerful, perfect bel canto balancing a velvety depth with piercing projection.  So how does she imagine an ideal bassoon tone?  She has heard endless advice about making a ‘dark’ sound, an adjective that seems equivalent to ‘beauty’ for many modern bassoonists.

Chiaroscuro

Our Little Bassoonist has studied 

If a dark room implies the absence of light, then a dark tone must imply the absence of – what?  Higher frequencies?  Or perhaps ‘dark’ just means an abundance of lower frequencies, like a room filled with shadows.  LB instinctively associates dark with low frequencies and bright with high frequencies and she’s on the right track.  But for a complete picture of bassoon tone, we need to consider the kind of frequencies.

In previous chapters, we have examined how bassoons harness the energy supplied by the pressure-controlled reed and animate the natural resonance frequencies of the bore via complex standing waves.  These true harmonics are selected by damping a broad range of unnecessary frequencies in the vibrating reed.  Along with embouchure, this interactive process described in previous chapters dampens unwanted elements of the reed’s overly broad tonal spectrum.   It is a bit like mixing paints: Caravaggio’s palette included primary colors, but he carefully muted and balanced his tints to achieve skin tones within the visual light spectrum.

When we first see a painting utilizing chiaroscuro – light/dark – we are as much struck by what is obscured in shadow as we are by what is revealed in the clarity of light.  A great bel canto voice presents a similar balance and an aspirational ideal for the bassoonist.

So, why is it that ‘dark’ is generally admired while ‘bright’ is often a pejorative?  I think one way to talk about these adjectives is to define them in terms of spectrum analysis.  In earlier chapters we looked at audio spectrum graphs, which focus on the frequencies of true harmonics.  These graphs show a certain amount of energy distributed among the fundamental and the overtones – for each note, each bassoon, each player and each reed.  While most of these spectrum outcomes are determined by the instrument itself, the reed and the embouchure play important roles by increasing or decreasing the relative strength of the many overtones.  A measurable increase in the lower harmonics leads to a sound often described as darker, while increasing the strength of the higher harmonics leads to a brighter sound.

Remember, while the specific frequency of each harmonic is defined by nature’s simple ratios to that of the fundamental, its relative strength (its amplitude as shown in the spectrum graph) can be modified to some extent by reed design and embouchure use.   Our Little Bassoonist wonders why we can’t measure the dark/bright balance of a reed by simply measuring its harmonic spectrum in real-time.  After all, we seem to have plenty of good audio spectrum applications using algorithms that convert a sound signal into a graphic representation of frequencies.  But these only take a ‘snapshot of the average levels of each of the component harmonics.  Much is left out of the evaluation, including the complex beginnings of notes – we call these attack transients – and the ongoing presence of unpredictable inharmonic components throughout the sustained tone.  It’s like the difference between a charcoal sketch and a full-blown oil painting.  The problem with relying too much on spectrum analysis is this: our ears are considerably more sensitive to complex sonorities than these simple computer applications.

The phenomenon of attack transients is common to all orchestral instruments: it’s the quick negotiation phase between initial energy input and the establishment of a steady, periodic regime of harmonics.  For the bassoonist, these range from the obvious (poorly vented mid-range attacks) to the subtle (perhaps that little chirp in tenor Eb?).   Once a steady tone is achieved, we become aware of inharmonic components that continue throughout the duration of a note.  You all know these as buzz, rattle, sizzle or just plain ‘noise’.  So, while a spectrum graph may clearly show energy peaks in the first 5 or 6 true harmonics – suggesting a dark sound – the brighter inharmonic transients simply won’t appear on the graph.  Those components not being generated by the bore of the bassoon are too ephemeral to be easily quantified.  Instead, these are reed-generated frequencies – non-harmonic and unpredictable – and they can contribute a LOT to the character of the bassoon tone.

There is an analogy to be made to a spoken conversation between two people, where words and ideas may be deep and resonant despite the occasional stutter or mispronunciation.  We should keep in mind that the bassoon/reed dialogue ultimately aspires to emulate singing.   Spectrum analysis tells us something about what is true in the acoustics of sound production, but actual listening reveals what we deem to be beautiful.

It should come as no surprise that a reed constructed from organic material and cleverly sprung to maximize energy input and acoustic output will naturally contribute all sorts of extra frequencies.  Good reed making strategies, combined with skilled embouchure, regulate these anomalies.  We’ve examined throughout this blog that the bore of the bassoon does the lion’s share of the work, setting up a regime of organized standing waves and discouraging non-harmonic oscillations, but the bassoonist’s lips and blowing strategies play important roles in attenuating unwanted sounds.

2021 is Franco Corelli’s centenary.  Thank heavens we don’t need spectrum analyzers to appreciate his tonal resonance and complexity.  But aren’t you a bit curious….?  I suspect that the unmatched squillo in his voice was achieved by the cultivation of fairly true upper harmonics.

In a long orchestral career, I have tried to balance my instinctive preference for a ‘covered’ sound with the need to project in a large theatre.  Too dark a sound can lead to a lack of both clarity and projection.  Students of my generation were told to ignore the closeup noise of a reed, with the understanding that transients and inharmonics would be largely attenuated by distance.  I was often advised that without some sizzle I wouldn’t project.  Of course, this advice has a logical basis; human ears perceive higher frequencies with more clarity.  You will always hear a piccolo carry over a viola.

Distance is critical in an art gallery, too.  Imagine you are standing inches away from a Rembrandt, close enough to see the brush strokes and tiny splashes of colour.  An eye springs to life with a mere speck of white dabbed on an iris.  Up close it’s a bit messy, but at a distance it seems utterly refined.  But are we bassoonists necessarily obliged to follow the same principle, using inharmonic ‘tints’ to project rich character to an audience?

Each of us bring our personalities to our tone production.  Some of us are bold and outspoken, others naturally understated.  Many bassoonists love to produce some extra ‘stuff’ in their reeds – a touch of frizzante if you like.  Experience has taught them that an overly sizzly sonority is often heard at a distance in perfect balance.  Others [I include myself] are more inclined to produce a ‘finished’ up-close tone.  The question is: while a sparkling reed will darken at a distance, will a velvety, covered reed actually go the distance??

A critical question for our role in the symphony orchestra.  The answer depends on several rather large factors:

  • some bassoons produce a broader and more complex range of component harmonics
  • some concert halls are more friendly to the lower range instruments of the orchestra
  • some ensembles are simply more transparent and balanced than others.

Projection is never just an acoustical quality; it’s about understanding when to play louder, use vibrato to increase tonal complexity or employ exaggerated nuance to help your musical personality carry.  A well-shaped phrase supported with a well-developed airstream will travel an extra 50 feet.  Musical depth and respect for your acoustical environment are as important as skillful reed making in achieving projection.

I had the great fortune to spend the first few decades of my orchestral career working in both a frequently recorded symphony orchestra and a separate radio orchestra.  These gave me an opportunity to listen to my sonority and projection in both a large concert hall and a recording studio.  As my reed making and my musical abilities evolved, I was able to evaluate my sound development on broadcasts a couple of times a month for many years.  The experience persuaded me that a reed that is satisfying up close can also achieve good projection in the concert hall.  The key is maximizing the strength of the higher harmonics while minimizing unwanted transients and inharmonics.  

Our little bassoonist [Miss Caravaggio, now] is looking for some simple rules to guide her in mixing her tonal palette.

So, here are some principles to consider…

So much of the character of the bassoon, or any instrument for that matter, depends on the first few milliseconds at the start of each note.  This is the opening dialogue between bassoon and reed when initial non-periodic frequencies are quickly dampened by the dominating standing wave regime within the bore.  These attack transients, in their most obvious form, are the reason we use flick keys, discouraging the lower 1st harmonic by creating a disruptive leak in the tenor joint.

Attacks grow more complex as we ascend the ladders of the various ranges; how much of these transients we choose to employ will depend on our artistic personalities.  Many players [mea culpa] work to minimize the presence of unwanted harmonics in the upper register attacks, while others love to have the extra character in their articulations and cultivate profiles that deliver these ‘peppier’ attacks.  Of course, these choices can also be repertoire-driven.

While attack transients are most obvious at the beginning of tongued notes, they also remain subtly present in legato passages.  Slurring between adjacent notes within one register tends to reduce the interactive dialogue between bore and reed to an absolute minimum, yet some reed profiles will exaggerate even these very minimal components.  Once a sustained tone on any note is achieved, we can begin listening for some of the ‘extra stuff’ in the sound: transient/impermanent components that bubble up to the surface.

If you’ve ever played on a plastic reed, you will immediately notice the absence of all of this ‘extra’ acoustical information!  Arundo donax has unpredictable, complex internal structures that contribute tonal complexities mostly absent in a synthetic reed.

Loudness plays an important role in the contribution of transients in the sound.  The louder you play, the greater the tendency for the ‘extra stuff’ to emerge.  Bassoonists tend to rely on a rebalancing of dark and light to exaggerate the effect of a crescendo.  The typical change of character between piano and forte can be an essential tool in establishing our personal tonal objectives.  Some players choose profiles that utilize significant increases in non-harmonic content during a crescendo.  Others will prefer to utilize ‘noise filtering’ strategies in their reed trims – often by using thicker profiles and larger overall dimensions.  My observation over the last 50 years of orchestral bassoon playing is that we’ve seen a shift in the dark/light preferences of performers and conductors.  You could say that bassoon tone has become ‘warmer’ – although that is a highly subjective description.  You could also say that bassoon tone is simply ‘darker’ than it was decades ago.

We have already established that the word ‘dark’ is a confusing concept.  I think a better description might be that we’ve undergone a shift in our ideals of refined bassoon tone.  Bassoonists understand the importance of true higher harmonic frequencies in their sound production but are a bit more cautious now in controlling transients in attacks and avoiding too much buzz at higher volumes.  What has emerged is the idea of a chiaroscuro that cultivates both shadow and clarity but leaves some of the rougher character of cane in the marshes where it grew.

At this point in yet another challenging chapter, our little bassoonist needs some guidance as she takes a knife to her reeds.  So, let’s look at a really simple principle that governs certain kinds of vibrating objects:

  • Non-harmonic content is inversely proportional to dampening [a vibrating system with a longer potential decay period]. It will take the dialogue between bore and reed longer to establish a steady regime of harmonic oscillation.
  • Conversely, a vibrating object whose natural frequencies are quickly dampened will demonstrate shorter attack transients and fewer non-harmonic components.

Here is a thought experiment: imagine your reed’s natural frequencies could be induced by whacking it against your knee like a tuning fork.  You can sort of imagine the reed briefly ringing like this, but the sustained ringing of cane is significantly shorter than the steel tines of the tuning fork.  You can also imagine that a thinner profile will vibrate longer than a thicker profile, as will a reed constructed with more resilient cane.  The more wood left on the profile, or the mushier the wood, the quicker this dampening process occurs.  Quick decay reduces transients.

A possible way to visualize the relationship between long decay and non-harmonic behavior would be a very loosely strung guitar string.  Pluck it and the string will vibrate wildly, buzzing and colliding with the fingerboard.  But as the string is gradually tightened and brought up to pitch, you will see it quickly organize into predictable waveforms.

Many experienced reed makers begin with profiles that are intentionally too thick and patiently remove cane to achieve adequate compliance (sufficient vibration).  Heavy reeds in that early trimming process generally demonstrate very little in the way of attack transients or extra ‘noise’ in the sound.  And we probably don’t notice!  Usually, when we test overly thick reeds, we’re entirely focused on the resistance and the sharpness, so we probably won’t notice the absence of transient inharmonics.  Trimming down sharp, heavy reeds to proper MCA values will deliver properly tuned reeds with a broad spectrum of harmonics, but we have to be careful not to go too far.  And it’s not just to avoid flatness. Thinning reeds too much can lead to more buzz in fortissimo and more pop in the attack than we might like.

There is certainly not a correct light/dark balance: chiaroscuro is a highly subjective concept in both art and music.  Corelli found his by combining bel canto techniques with lucky genetics in his vocal physiology.  Maybe our Little Bassoonist will find hers adapting reed profiles to match her lips, teeth, mouth, air column AND artistic temperament.  But she’ll do better if she can understand the main source of the ‘extra stuff’.

Bassoonists who prefer smaller reeds need to remove more cane to play with resonance in the A=440 world.  Success here typically involves specific profile strategies.  For example, some of our great players make reeds with very thin ‘channels’ as a way to deliver adequate compliance.  Others rely on a stiff spine and let tip and sides vibrate more freely.  There is always an acoustical requirement to match cane flexibility and reed dimensions.  Smaller reeds have less margin for error in finding correct MCA values without losing control of chiaroscuro. 

When done well, these lighter reeds become Corelli in character, with boosted higher partials and just a touch of inharmonics.   They’re fun to play, too.  Bigger reeds, using larger and thicker profiles, produce smoother and woodier sounds with more relative energy in the lower harmonics, a bit less of the upper harmonics, and much less transient character in the attacks.

Let’s give LB a simple rule:

  • Profiles that feature very thin areas will tend to produce more of the transient frequencies in the attacks and more tendency towards brightness and inharmonic noise in louder dynamics.
  • Profiles with thicker cane will tend to produce less of these transients

Think like Caravaggio!  Thicken your sound with dark umber before gradually thinning to an iridescent silver. 

Finally, please consider this: like Corelli, your ideal bassoon tone is an unavoidable extension of your body and your personal identity.  It will be tightly linked to your physical tolerances and tonal preferences.  Your responsive embouchure and adaptive air column are critical in emulating the human voice.

Like Corelli, you’ll need to balance the light with the dark! 

Read more about Christopher Millard. Chapter 1 – The Craftsman Chapter 2 – Can you explain how a bassoon reed works? Chapter 3 – Surf’s up! Chapter 4 – The Physicist’s Viewpoint Chapter 5 – The Big :Picture Chapter 6 – We’ll huff and we’ll puff… Chapter 7 – Look Both Ways Chapter 8 – Dialogue Chapter 9 – The Big Bounce Chapter 10 – The Incredible Shrinking Bassoonist Chapter 11 – A Useful Equation  Chapter 12 – Goldilocks’ Dilemma Chapter 13 – Stairway to Heaven  Chapter 14 – Reed MyLips Chapter 15 – Resonance Chapter 16 – Corvids & Cacks Chapter 17 – Lift  Chapter 18 – Chickens and Eggs Chapter 19 – Chiaroscuro Doodles & Design by Nadina

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