Analysis and Prediction of Mid-High Peak Frequency for Microspeaker with Side-Firing Front Chamber

Abstract

The generating mechanisms of the mid-high-frequency peaks of a sound pressure level are theoretically investigated in this study with a side-firing front chamber. A mid-frequency peak is caused by the Helmholtz resonance phenomenon of the front chamber, and a high-frequency peak occurs owing to tube resonance. The electromagnetic–mechanical–acoustic coupling method (E–M–A) and resonance equations are used to obtain the sound pressure level and peak frequencies, respectively. Seven side-firing front chambers have been designed with respect to different tube lengths, tube widths and tube heights. Microspeaker samples with different front chamber designs are manufactured to verify the analytical results. The SPL and mid-high peak frequencies comparisons showed good agreement between the analysis and experimental results.