Numerical investigation and actuator design for Advanced Digital Sound Reconstruction

The actuator design for a new method of sound generation – which we call Advanced Digital Sound Reconstruction (ADSR) – is a very challenging task due to the increased complexity of the actuator compared to a standard loudspeaker. The basic principle of ADSR relies on the generation of purely positive or negative sound pulses, which can be achieved by equipping a membrane with shutter gates. Combining multiple of these actuators and superimposing the sound pulses enables the generation of an audio signal. The actuator itself is designed as a Micro-Electro-Mechanical-Systems (MEMS) device since ADSR requires a highly dynamic actuator. Due to the small scale, viscous effects have to be taken into account. Furthermore, the shutter gates used for the separation of sound pulses introduce additional sound emissions which have to be mitigated. Based on these challenges, numerical investigations using the linearized flow equations in order to solve for the acoustic pressure have been performed. We present studies on the influence of different parameters on the acoustic transmission properties of the actuator in order to optimize the system. The results of the parameter study are finally translated to design guidelines in order to aid in the early design stages.