<str<strong>on</strong>g>CIM09</str<strong>on</strong>g> 26-29 octobre 2009Sounding aesthetics and recorder chamfersFrançois Blanc 1 , Philippe Bolt<strong>on</strong> 2 , Pierre-Yves Lagrée 3 , Benoît Fabre 11- LAM – Institut Jean le R<strong>on</strong>d d'Alembert – UPMC Université Paris VI (France)2- Recorder maker (France)3- FCIH – Institut Jean le R<strong>on</strong>d d'Alembert – UPMC Université Paris VI (France)BACKROUND IN INSTRUMENT MAKINGRecorder makers probably began to put chamfers <strong>on</strong> their instruments, at the windway exit, very early<strong>on</strong>. They can be seen <strong>on</strong> most of the surviving original recorders from the Renaissance to the Baroqueperiods, and probably existed <strong>on</strong> recorders earlier still.Their size varies from 0.5 to 1.5 mm, and their angle is often around 45°, but can be steeper or shallower.Their adjustment is intricate, but they do make all the difference to the sound quality and speech of therecorder. An instrument without chamfers is uncertain in speech <strong>on</strong> some notes, and unstable <strong>on</strong> others.There does not seem to be any known rule c<strong>on</strong>cerning them, and each maker seems to have his style, whichinteracts with the other parameters of the windway and bore profile.Makers usually know what they are aiming for when they cut and adjust the chamfers at the end of thewindway and the block, but have little knowledge as to why they have this effect <strong>on</strong> the instrument'smusical quality.BACKGROUND IN PHYSICSIn the recorder, an unstable jet blown by the player interacts with the labium, resulting in aeroacousticalsources. The res<strong>on</strong>ator of the instrument amplifies the acoustic field around its res<strong>on</strong>ance frequencies. Theacoustic field from the res<strong>on</strong>ator disturbs the jet in return, and the perturbati<strong>on</strong>s grow al<strong>on</strong>g the path of thejet before reaching the labium. This leads to an auto-oscillati<strong>on</strong>. A model has been developed, showing howthe jet receptivity to an acoustic perturbati<strong>on</strong> depends <strong>on</strong> the shape of the exit of the channel.AIMSThe model developed may give clue to the understanding of the maker's gestures. In particular, it isexpected to partially explain why rounded geometries are usually forbidden in the making of recorders.Then, <strong>on</strong>e may explore the possibility given by geometries different from the <strong>on</strong>e traditi<strong>on</strong>ally used in themaking of recorders.MAIN CONTRIBUTIONDifferent recorders are played and recorded. Each instrument is made according to the making rules froma certain musical era, and witnesses of a sounding aesthetics. The main differences between the instrumentsstand in the bore. The sound are analysed, and differences in the spectral c<strong>on</strong>tents are exhibited.A prototype recorder, which channel exit can be changed, is also played. Measurements of the blowingpressure allows to focus <strong>on</strong> the differences in playing, depending <strong>on</strong> the geometry. Changing the geometryof the channel exit changes the overall t<strong>on</strong>e and appropriate blowing of the instrument, and may inducedifferent sound aesthetics.REFERENCESSégoufin, C.; Fabre, B.; Verge, M.; Hirschberg, A. & Winjnands, A. P. J. (2000). Experimental study of the influenceof the mouth geometry <strong>on</strong> sound producti<strong>on</strong> in a recorder-like instrument windway length and chamfer.Acta Acustica united with Acustica, 86, 649-661.Fabre, B. & Hirschberg, A. (2000). Physical Modeling of flue instruments: a review of lumped model. Acta Acusticaunited with Acustica, 86, 599-610.Verge, M.; Fabre, B.; Mahu, W. E. A.; Hirschberg, A.; van Hassel, R. R.; Wijnands, A. P. J.; de Vries, J. & Hogendoorn,C. (1994). Jet formati<strong>on</strong> and jet velocity fluctuati<strong>on</strong>s in a flue organ pipe.Journal of the Acoustical Societyof America, 95(2), 1119-1132.Wolfe, J.; Smith, J.; Tann, J. & Fletcher, N. H. (2001). Acoustic impedance spectra of classical and modern flute,243(1), 127-144.Coltman, J. W. (1968). Sounding mechanism of the flute and organ pipe. Journal of the Acoustical38 <str<strong>on</strong>g>CIM09</str<strong>on</strong>g>
26-29 octobre 2009 <str<strong>on</strong>g>CIM09</str<strong>on</strong>g>BIOGRAPHIESFrançois BlancFrançois Blanc is a PhD student in the field of the physics of the flue instruments at the UPMC university, in Paris.Bolt<strong>on</strong>Philippe Bolt<strong>on</strong> is a recorder maker based in Villes-sur-Auz<strong>on</strong>, in France.<str<strong>on</strong>g>CIM09</str<strong>on</strong>g> 39
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