Patent ID: 7894614

Claim:
An improved low-frequency loudspeaker apparatus, comprising: a loudspeaker driver that produces a cone excursion and is characterized by a maximum cone excursion; a box for housing said loudspeaker driver; a port in said box for tuning the box to a box tuning frequency whereby the combination of the loudspeaker driver and the box and said port have a first frequency response; a power amplifier for energizing said loudspeaker driver; an equalizer for altering said first frequency response to become a second frequency response and for providing a signal to said power amplifier; a signal input means connected to said equalizer; said first frequency response having a second-order high-pass frequency response characteristic whose amplitude at the box tuning frequency is substantially below the reference response level; said equalizer being characterized by a maximum equalization gain; said equalizer having a third frequency response, said third frequency response having a second-order biquadratic characteristic whereby said second frequency response is flat to substantially lower frequencies than those frequencies to which said first frequency response is flat.