PROGRAMM - DAGA 2012

220 DAGA 2012 ProgrammMi. 17:45 hassium 3.02 Akustische Messtechnik 1Estimation of lumped transducer parameters under considerationof visco-elastic behavior and acoustical loadsH. Gregor a und W. Klippel a,ba Klippel GmbH; b TU Dresden, Institut für Akustik und SprachkommunikationModern multimedia and telecommunication applications demand smallerspeakers driven over the whole audible frequency range. This resultsin an extended transducer model and new demands on the identificationof the model parameters. In particular modeling the mechanical part of atransducer as a spring-mass-system is not sufficient to describe the behaviorof micro-speakers below the resonance frequency where viscoelasticitycauses for example the creep effect to occur. Most methodsestimating the parameters of a lumped transducer model use an impedancemeasurement to derive the parameters of the electrical and themechanical system as well as an additional method (e.g. perturbation orlaser method) for measuring the mechanical parameters. The introducedmethod combines several measurements of the impedance and thedisplacement in air and vacuum. The displacement is measured at differentpoints of the membrane, which makes the estimation more robustagainst rocking and other vibration modes. The additional measurementin vacuum allows a separation of the acoustical load from the electromechanicalsystem. Thus an estimation of the acoustical load becomespossible.Mi. 18:10 hassium 3.02 Akustische Messtechnik 1Auralization and Assessment of Loudspeaker DistortionM. Liebig a und W. Klippel a,ba Klippel GmbH; b TU Dresden, Institut für Akustik und SprachkommunikationLoudspeaker distortion generated by a rubbing voice coil, loose particles,parasitic vibrations, air leaks or other loudspeaker defects have ahigh impact on perceived quality of audio systems. Measurements duringthe development process and at the end of the assembly line areperformed to assess the product in an objective way by using specificationsand PASS/FAIL limits. However, limits need to be defined withrespect to the target quality required in the particular application, cost,weight, size and other constraints. The definition of those quality limitsis often a critical moment in the dialog between customers, suppliers,engineering and management as well. This paper presents a new auralizationtechnique which is capable of enhancing and attenuating thedistortion in the reproduced sound by dispensing from a physical modelof the distortion generation process and using test stimuli, music or anyother audio signal. The perceived sound quality is predicted by usinga perceptive model of the auditory system based on ITU-R BS.1387-1