Frequency spectrum of a clarinet

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The clarinet behaves like a closed-end pipe, theoretically allowing only odd harmonics, but measurements show that even harmonics also have significant amplitudes. The app "SpectrumView" was used to analyze the clarinet's frequency spectrum, revealing that odd harmonics are present but less pronounced than expected. This discrepancy may be due to the clarinet's real-world characteristics, which do not perfectly align with ideal closed or open pipe models. Reed resonances in the clarinet contribute to this filling of the spectrum, making the closed-pipe nature less distinct. Further resources on clarinet acoustics can provide additional insights into this phenomenon.
greypilgrim
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Hi.

Usually, the clarinet is presented as acting like a pipe system closed at one end, which only allows for harmonics that are odd multiples of the fundamental frequency. I used the app "SpectrumView" by OxfordWaveResearch to measure the following spectrum:
20180619_163908000_iOS.jpg


Fair enough, the amplitudes of the odd harmonics are considerably smaller than the ones of the even harmonics, but far from "absent". I assume that no real-world system satisfies boundary conditions such as "closed pipe" and "open pipe" perfectly and are a mixture between them, but I still would have expected the amplitudes of the odd harmonics to be much smaller.

Is something wrong with my measurement, or is the closed-pipe-nature of a clarinet really THAT indistinct?

As a comparison, the spectrum of the G string of a guitar (which resembles a pipe closed at both ends), which has the same fundamental frequency:
20180619_164045000_iOS.jpg
 

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The short answer to your question is that there are reed resonances in the clarinet that fill in the spectrum. There is a wealth of information on clarinets and other instruments here
http://newt.phys.unsw.edu.au/music/clarinet/
 
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