Comparing Clarinet Grunt and Squeak Notes to Transitions in Coupled Oscillators

Under certain circumstance, a clarinet can cause an undesired squeak or grunt note. A squeak note is the clarinet shifting to a higher register - a higher set of harmonics - while a grunt note is the clarinet shifting to a lower register. One might hypothesize that such changes occur naturally in the clarinet over time. Analysis of such transitions with waterfall plots reveals a similarity to transitions made with thermoacoustically-driven coupled oscillators. For coupled oscillators, transitions can occur when the resonance of one oscillator passes through that of the other. This suggests that the cause of the undesired transitions in the clarinet are the result of one resonance (possibly the reed, which is affected by the embouchure) passing through that of the resonance of the other (likely the bore) rather than the clarinet itself relaxing to a different register as a function of time. Various notes played on an artificially-blown clarinet are found to shift in seconds while others are found to play over a length of thirty seconds. This suggests that the reed-embouchure system has a factor in grunt and squeak notes.