Frequency spectrum of a clarinet

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SUMMARY

The clarinet exhibits a frequency spectrum that deviates from the ideal closed-pipe model, allowing for both odd and even harmonics. Measurements taken using the "SpectrumView" app by OxfordWaveResearch reveal that while odd harmonics have smaller amplitudes, they are not absent, indicating the influence of reed resonances. This suggests that real-world clarinets do not perfectly adhere to theoretical boundary conditions, resulting in a complex harmonic structure. The discussion highlights the need for further exploration of the clarinet's acoustic properties.

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  • Understanding of harmonic series and frequency spectra
  • Familiarity with acoustic principles related to wind instruments
  • Experience using audio analysis tools like SpectrumView
  • Knowledge of reed instrument mechanics and resonances
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Musicians, acousticians, music educators, and audio engineers interested in the acoustic behavior of wind instruments, particularly clarinets.

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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