PROGRAMM - DAGA 2012

Programm DAGA 2012 217on taking transfer functions between the scanning transducer and thereference sensor. Then, the number of positions measured is limited foreach frequency evaluating the dynamic range acquired. Some experimentalresults of mapping sound radiation patterns of a musical instrumentare presented along with a discussion focused on the advantagesand disadvantages of the method.Mi. 15:15 hassium 3.02 Akustische Messtechnik 1Development of a Low-Cost Characterization System for Feed-Forward ANC HeadphonesW. Moitzi a , M. Schörkmaier b und M. Fellner ca TU Graz; b Austriamicrosystems AG; c Joanneum Research, GrazThe performance of a properly-working feed forward ANC system mainlydepends on the accurateness of the implemented filter curves. Toachieve good attenuation levels, these filter curves have to be evaluatedindividually for every headphone type. The measurement processfor the evaluation of the required filter has, until now, been considereda complex process. Assuming an acoustically optimized measurementchamber makes the process inflexible. High-performance hardware, likemeasurement microphones, pre-amplifier and the IEC 711 standardcoupler are expensive and, additionally, require in-depth knowledge ofacoustics to diligently perform measurements. Last, but not least, thepace of the measurements marks an important point towards supportingcost-optimized product development. The aim of this thesis is todevelop an all-in-one low-cost solution which includes the adaptation ofthe measurement environment, resulting in downsizing from room sizeto the required manageable size, the development of the necessaryhardware components, like the acoustic coupler based on the IEC 711standard coupler, and the development of measurement software, includingan easy-to-handle GUI. The finalized measurement system shouldallow fast and easy characterization of ANC headphones in an office environment.An additionally-developed ANC performance evaluation toolshould allow determination of the active headphone performance.Mi. 15:40 hassium 3.02 Akustische Messtechnik 1Optimized Measurement System for the Synthesis of TransferFunctions of Variable Sound Source DirectivitiesJ. Klein, P. Dietrich, M. Pollow und M. VorländerInstitut für Technische Akustik, RWTH AachenDuring previous research, Kunkemöller et al. (DAGA 2011) developeda measurement procedure to synthesize room impulse responses forarbitrary target source directivity patterns by superposing single measurementsconducted with a multi-channel source of known directivity. Thesingle measurements are decomposed into their spherical harmonic basefunctions. By applying a single matrix inversion, it is then possibleto generate a synthesis vector, with the help of which it is possible to