Audio bass speaker driver circuit

Abstract

A bass audio circuit includes a first filter network (11) which receives left (12) and right (13) channel input signals and produces two filtered signals (14) by attenuating frequencies in the input signals above a first cutoff frequency. The two filtered signals are summed (15) to create a first monophonic signal (16). A second filter network (22) produces attenuated frequencies in either the input signals or in the first monophonic signal that are above a second cutoff frequency which is lower than the first cutoff frequency. The signals (23) from the second filter network are combined (24) and passed through a phase inverter (26) to derive a second monophonic signal (27). An output stage (17) individually amplifies the two monophonic signals (16, 27) which then either are applied to a dual voice coil woofer (31), or are electrically summed and applied to a single voice coil woofer. Alternatively, the two monophonic signals are first summed and applied to a single channel amplifier which drives a single voice coil woofer. This audio circuit adjusts the relative emphasis of psychoacoustic elements of the bass signals to accurately emulate the bass performance of the sound being projected and enhances performance of a woofer driver by limiting extremely low frequency displacement.