VITA 2010

	Vienna Talk 2010 on Music Acoustics "Bridging the Gaps" September 19–21

List of Vienna Talk 2010 presenters

Amir, Noam (P,O)

Andermann, Martin (P)

Arzt, Andreas (O)

Bastos, Patricia Lopes (P)

Beauchamp, James Warren (O,O)

Bendl, Ingrid (P)

Bertsch, Matthias (P)

Bisesi, Erica Elisabetta (O)

Buen, Anders (O)

Campbell, Murray (O)

Cano, Estefania (P)

Carral, Sandra (P)

Carter, Stewart Arlen (O)

Chatziioannou, Vasileios (P)

Chick, John (O)

Curtit, Marthe (O)

Dalmont, Jean-Pierre (O)

Davidenkova, Ekaterina (O)

Demoucron, Matthias (O)

Doutaut, Vincent (P)

Dörfler, Monika (O)

Flossmann, Sebastian (O)

Fouilhe, Eric (O)

Fricke, Jobst P. (O)

Fritz, Claudia (O)

Gingras, Bruno (O)

Goebl, Werner (P)

Granzotto, Nicola (P)

Grosshauser, Tobias (O)

Guettler, Knut (O)

Hansen, Uwe J (O)

Kartofelev, Dmitri (P)

Kausel, Wilfried (P)

Kemp, Jonathan (O,O)

Presentation type: Oral / Invited

Wave separation and non-linear effects during super-high note playing in brass instruments.

The subject of super high notes in playing the trumpet or horn is a current area of controversy. Playing these notes might be expected to involve vibrating the lips at a frequency higher than the cut-off frequency of the horn predicted by linear acoustic theory. No reflections of acoustic energy would thus influence the player’s lip vibration. This would in turn imply that the notes would not be controlled by the instrument resonances. Statements by players contradict this theory in that they report that the super-high notes are “slotted” in that the instrument resonances influence the notes that can be played in the super-high range.

It is well known that non-linear effects occur in brass instruments in playing loud notes. This has been demonstrated by various researchers, for instance by measurement of the pressure signals which show a far greater number of harmonics at the bell in comparison to the mouthpiece. Recent research has demonstrated separation of forward and backward going waves while a horn is being played. This study will work towards wave separation within an instrument bore to demonstrate whether reflections from the instrument influence lip vibration and whether non-linear effects are always present during super high note playing.

Presentation type: Oral

Radiation and reflection in a rectangular cross-section waveguide: finite difference simulation and theoretical frequency domain impedance.

If a theoretical expression is known for the radiation impedance then it may be projected to predict the input impedance and input impulse response in an acoustic waveguide. Radiation impedance may be derived from integration of Green’s functions and so are based on continuous expressions in the frequency domain.

In this study the finite difference technique will be used to simulate the reflections of a band limited impulse as it travels down a horn and partially radiates and reflects from the end. The finite difference technique used here is based on approximating the 3 dimensional lossless wave equation using differences between adjacent grid points to calculate differentials. These calculations will be performed for a discretized 3D rectangular horn within a large discretized 3D box whose walls may be set to absorb incident energy.

The finite difference results will be used to create animations to visualise the pressure field at the point of partial reflection and transmission of a band limited impulse in the time domain. Frequency domain analysis will then be used to compare the results with those predicted by the frequency domain impedance techniques.

Klaus, Sabine Katharina (O)

Kostek, Bozena (O)

Lambrechts-Douillez, Jeannine (O)

Lohri, Angela (P)

Marchand, Sylvain (O)

Mayer, Alexander (P)

Moore, Thomas (O,O)

Morrison, Andrew (O)

Myers, Arnold (O)

Nederveen, Cornelis J (O)

Niedermayer, Bernhard (O)

Norman, Lisa (O)