Why are wind instruments made out of what they’re made out of?

The way instruments in the orchestra look has become such a standard thing that any changes would be instantly noticed as quite odd. Woodwind instruments are made out of a variety of different materials for the purposes of best suiting their sound and their construction. Tradition plays a part, but is often less important. But what led these materials to be used, and what exactly do they do to the sound?
Most wind instruments, such as the oboe, clarinet, flute and recorder were traditionally made from boxwood, a very light wood that was relatively easy to come by in the 18th century. Since this time, these instruments have been changed to be made out of grenadilla, resin, metal and plastic. While partly to do with manufacturing advances, since cast resin and plastic weren’t an option in the classical period, most of the change in construction has been to change the sound.Nicola Boud with a classical boxwood clarinet, from the Halcyon Ensemble website

To demonstrate this, only a small physical example is necessary. A metal tube struck with a stick will produce a long ringing tone in comparison to wood, both because the hard nature of the tubing makes the air inside and around it more likely to rebound and reverberate rather than losing it’s sound energy, and because it’s naturally a property of metals to be sonorous(produce a ringing sound when struck). Similarly, looking at wood, if you hit a hard hollow log with a stick, it will produce a brighter(albeit still wooden) sound than if you hit a soft or rotting hollow log with a stick. This is because the log is acting as a reverberating chamber, and if it is made of hard wood, the soundwaves in the air inside will more likely be able to produce a louder sound because less of their kinetic energy(which is what sound is) would be lost hitting the hard wood when they bounce around inside. Similarly, a softer wood would absorb more of the sound waves’ energy as they bounce around.

Any wind instrument acts as it’s own reverberation chamber, unlike string instruments, in which the body is a specially made cavity for this purpose. In wind instruments, this means generally that more projection and volume can be gained by using hard woods such as grenadilla, and most wind instruments are made from this today. An exception to this is the bassoon, which uses maple. Still a relatively hard wood, this can be seen as something of a compromise in giving the bassoon a gentler sound. Tradition here also plays a part, but material is possibly slightly less of a factor in bassoons because almost half of the tubing inside the instrument is covered with a hard rubber coating to prevent damage from moisture(this is just from the research I have done, I might be wrong, if there are any bassoonists who know better I’m very curious and would love to hear from you!). The change in dynamics between instruments of different eras is easily seen if you hear the difference between modern and classical flutes. In fact, it is often a difficulty of flautists playing period instruments to be heard over their accompaniment!

oboe

A classical oboe. Note the boxwood construction which would probably not easily support the complex key mechanisms on the modern oboe

If a hard substance like metal would give the best projection, why aren’t all wind instruments made out of metal like the flute? Manufacturing and the tone people have grown attached to plays a part. Saxophones’ huge sound comes from both their conical bore and their brass creation, brass being an alloy known for it’s sonority. But the dark, rich tone of the clarinet is in part due to it’s wooden body, and the fullness of the oboe likewise. Grenadilla is a relatively rare wood only growing around the equator and is much easier to aquire now than it was in the 1700s. One of the reasons that flutes made the early jump to metal was that is was easier to manufacture a straight metal tube to hold all the pins required for keywork when keys became more complex. For clarinets and oboes, this posed less of a problem because grenadilla if treated properly was much stronger than boxwood, and by this point keywork had changed to be more suitable on wood anyway. Also, the subtle changes in the way the bore tapers in clarinet and oboes was easier to spin out of wood than metal, at least in this time period. Despite this, metal clarinets, bassoons, and oboes have all been made, but none really gained popularity, as they went against the established construction and established sound.

I apologize if this article has been a bit ‘heavier’ than the last few, but it’s not easy to summarise development of woodwind instruments over 300 years all that succinctly. But hopefully it’s shed a little bit of light on why things are made as they are. If anyone is interested in the acoustics of instruments, a page about this can be found at the UNSW page here, and it explains all terminology in good and understandable detail. If there are any questions about this topic, I’ll be happy to try and answer them

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