Parametric simulation study of miniature loudspeaker for performance evaluation and improvement

Sound reproduction in a limited space with accumulation of functions for polyphonic sound is increasing demand of 4C products. Miniature loudspeaker has to generate smooth sound pressure level (SPL) over range of 100 Hz to 10 kHz as per requirements of 4C products. In this study we reports formulation and validation of equivalent circuit model for miniature loudspeaker. This is achieved by measuring electroacoustic (Thiele-Small) parameters and performing anechoic chamber measurements. The validated model is then simulated for investigating the effect of key parameters of miniature loudspeaker based on our past experience. Such parameters are transduction factor, electrical resistance of voice coil, electrical impedance of voice coil, mass of diaphragm, resistance of diaphragm, and compliance of diaphragm. These parameters are adjudged based on TS parameter and their effect on SPL. This study investigates the effect of parameters in two layer manner. In the first layer, diaphragm dependent mechanical parameters and voice coil dependent electrical parameters are isolated and simulation is carried out. We found very promising results. With these results, in second layer, an attempt is extended to combine them to get better information on the effect of these parameters on the SPL of miniature loudspeaker. Finally, an improvement in performance of miniature loudspeaker is obtained for reduction in fundamental resonance frequency, reduction in second resonance peak, increase in the bandwidth, increase in low frequency response and increase in SPL over complete range by careful tuning of these parameters.