Today I want to talk about bocals.

If your spell check is anything like mine, it probably just underlined that word as an error (bonus points if it suggests that “low-cal” is what you were really going for!), but I assure you, that is correct. Which, naturally, leads to the question “You’re talking about what, now?”.

Bocals. I’m talking about bocals. You know, these things:

[Image courtesy of themusicgrove over at Wikimedia Commons]

Which is to say the little bit of metal tubing that goes from the reed (i.e. the bit you blow into) into the rest of the instrument in a fully assembled bassoon. At first glance, it might seem kind of innocuous, even boring. It’s a little tube with a couple of bends in it. Surely it can’t be that big a deal?

Oh, but it can. After the reed (which is the part that actually gets the air vibrating to set everything else in motion), the bocal is one of the most important parts of a bassoonist’s physical setup. Indeed, in some ways you could argue that it’s more important: Reeds are easy enough to change, after all, and as a bassoonist, you make (or buy) an awful lot of them; bocals are rather more difficult to modify, and it’s rare for even a professional bassoonist to have more than two or three.

Two or three? Why would you need more than one? Surely having enough pieces to put your instrument together once is enough?

Well. It turns out that not all bocals are made the same. Quite deliberately, in fact. There’s a whole host of variables that bocal manufacturers change to produce the things in a bewildering array of specifications. One of the most fundamental is the length — since the length of the air column inside the instrument determines the pitch, changing the length of the bocal changes the pitch of the bassoon as a whole. But, of course, it’s not obvious how best to measure a curve like that, and so instead of giving bocal lengths in centimetres or inches, manufacturers just mark them in integers, like with many clothing sizes. And, just like with clothes, these numbers don’t line up perfectly. So a Fox “1” might be pretty close to a Heckel “2”, but unless you memorize an extensive equivalency chart, the numbers are really only useful for comparisons that stick within a single brand.

Such comparisons happen a lot, because length is only the beginning of what you can change about a bocal. The material it’s made of is also up for grabs — is it steel? Nickel-plated silver? Brass? Palladium? If it can be made into a bocal, it probably has been; some people even swear by bocals made from wood. (Which immediately raises further questions: What kind? How long has it been seasoned? What, if anything, is it lined with? Truly bocal materials science is a bottomless well of possibilities.) You can also vary how much of the material there is: Thick–walled bocals often coexist alongside thin–walled versions made from the same stuff in the same length.

The material matters because it colors the sound in subtly different ways. Different materials have different resonant frequencies, which means that they’re going to amplify or mute certain frequencies as the air moves thru the instrument. Since tone color is the result of the balance between the frequencies of the sound in question, slightly altering that balance can have a dramatic effect on the color of the tone ultimately produced.

And this is where things really get going. Because it’s not just the material that affects those frequencies, it’s the specific shape of the curve itself. Exactly how much does it bend? Where do those bends start and stop? Do both sides do this the same way, or are there areas of greater and lesser parallelity? How conical is the bore, and how evenly is that distributed along the length? All these things and more change the quality of the sound that comes out the other end of the instrument.

How many combinations of these variables are there? Well. On the website of one major manufacturer, Heckel, they estimate that they produce nearly 6,000 different kinds of bocals*. And that’s just one brand (albeit the largest). To keep track of this, each manufacturer has an elaborate system of codes to mark a number of different styles, all of which multiply and combine in a bewildering proliferation. So you might use a Heckel BBD–Z, or a Fox CVX Double Star, or maybe a Leitzinger EF. (For those playing along at home, I use a Heckel CD–G 2. If you think I play with a nice tone [YouTube], 90% of it comes from that.)

With a little searching, you can find brand–specific breakdowns of what these codes all mean, but there’s little point in memorizing all of it, since the best way to find a bocal you like is just to try them out. And the best way to do that is to visit a store that specializes in stocking different bocals, which I had the opportunity to do a few years ago.

It’s the closest I’ll ever come to visiting Ollivander’s. The place I visited was a nondescript tenant in a strip mall on the outskirts of Chicago, but inside it was overflowing with stacks upon stacks of drawers of bocals. The proprietor brought out about a dozen to start, casting as wide a net as possible to feel out the general styles that worked well with my particular reeds and bassoon. Some of them were obviously wrong, either wildly out of tune or ugly in timbre or simply difficult to get notes out of**. But some of them seemed to be something of an improvement over what I was playing on before, and those brought forth a profusion of other options, a branching tree of bocal possibilities. After several rounds of this (including one where I tried out every single variation on the Heckel CD that they had in stock), I had narrowed it down to the three possibilities that seemed most promising.

But things that work well in the lab don’t always go the same way in the field, so the last round of testing was to take those three bocals back to New Haven and try them out in rehearsals and concerts. (It turns out that things that sound good in a small carpeted office space don’t always do so well in a concert hall. Who would have thought?) One of them was quickly revealed to be a dud — whatever virtues it seemed to have in Chicago evaporated on the east coast, and I was stuck deciding between the final two.

Both of them were very good bocals, but they emphasized different things. What ultimately tipped the scales for me was the solo at the start of the “Rufford Park Poachers” [YouTube] movement of Lincolnshire Posy (which I was playing in band at the time): With the bocal I ultimately went with, I could get a delicious silken purr out of the low register melody; the other bocal was brighter and harder-edged, harder to make blend with the other instruments in the ensemble.

I’m happy with that choice, and wouldn’t change it, but it’s not a choice without tradeoffs. The bocal I have is great for lyrical lines and blending into the background, but that means it sacrifices some punch and power. Projecting out over a large ensemble can be difficult, and I’m not always happy with biting out more aggressive accents. In addition, it definitely favors darker, mellower timbres, which makes it less well suited to French music and the brighter, clearer sound that repertoire calls for. This is why professional bassoonists often have more than one bocal. They might have a bright, cutting one for orchestral playing and a mellower one for chamber work, or one that can effortlessly pop out stratospheric high notes to balance out another that’s better at keeping the low register in tune. The possibilities are endless, and there are no perfect solutions.

As with the finer nuances of any profession, this is pretty esoteric stuff. But I think it’s cool to peel back the layers and peer behind the scenes, to get little windows into worlds that often remain hidden out of sight. So the next time you hear a bassoon in action, take a moment to consider the bocal. It may be a small and bendy thing, but it makes everything else possible.

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*And that’s just the ones they currently make. To keep the shape consistent, bocals are formed around very precise molds, and if those molds get damaged or destroyed, it’s not always possible to recreate them perfectly. When the Heckel bassoon factory was set on fire during World War II, the molds they used for bocals were destroyed, and even tho they tried to recreate them after the War, pre-war bocals still play noticeably differently than their post-war equivalents. Some people swear by them (with a fervor that can, at times, seem almost mystical, as tho the Secret Art of Excellent Bocal Making was lost in the conflagration and all we have now are degraded scraps in a tarnished age), but I’ve never had the chance to try one myself.

**Some of these differences are vanishingly subtle, but I was surprised by how many of them weren’t. I was also surprised by how different it felt to play some of them — even when I could get the same end result, there was a shocking range of effort involved; I was expecting to have to play on each one for a considerable time to detect things like this, but often it was apparent within less than a minute of playing. It turns out that when you’re dealing with something as intimate as the flow of your breath, you notice small changes fast.