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Sound Production in Recorderlike Instruments : I. Dimensionless Amplitude of the Internal Acoustics Field

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text
 

Genre(s)

article
 

Forme(s)

document imprimé
 

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Identification

Titre

Sound Production in Recorderlike Instruments
 

Sous-Titre

I. Dimensionless Amplitude of the Internal Acoustics Field
 

Nom(s)

Verge, Marc-Pierre (auteur)
 
Fabre, Benoît (auteur)
 
Hirschberg, Abraham (auteur)
 
Wijnands, A. P. J. (auteur)
 

Publication

1997
 

Description

Sujet(s)

acoustique instrumentale   recordlike instrument   recorderlike flue organ pipe   Strouhal number   dimensionless amplitude  
 

Résumé

Data on the internal acoustic pressure signals in an experimental recorderlike flue organ pipe are presented. A dimensionless representation appears to be a powerful basis for the analysis of these data. The dimensionless amplitude of the fundamental is, for a given geometry, a function of the Strouhal number only. For the first hydrodynamic mode of the jet, this amplitude is independent of the acoustic mode involved. The dimensionless amplitude of the second harmonic displays two different behaviors, depending on whether the jet is laminar or turbulent. This specific Strouhal number dependency implies a strong influence of the distance W from the flue exit to the labium on the timbre of recorderlike instruments. In recorders the ratio W/h, where h is the height of the flue exit, is adjusted by craftmen of a value close to 4. This specific ratio ensures an optimal harmonic content to noise ratio in the produced sound. Increasing the distance W yields a more powerful sound but at the expense of additional turbulence noise. For these large ratios W/h, transitions between different hydrodynamic modes of the jet are observed at low blowing pressures. This phenomenon is avoided by the choice of a recordlike geometry.
 

Note(s)

Article paru dans : JASA: Journal of the Acoustical Society of America vol. 101 n°5
 

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Date de la notice

2006-03-14 01:00:00
 

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