Low frequency equalization for loudspeaker system

Abstract

A method of optimizing the low frequency audio response emanating from a pair of low frequency transducers housed within a cabinet. The low frequency transducers are electrically connected to a power amplifier and source of audio content. The resonant frequency (Fs) and amplitude (Q) are characterized as to the high-pass pole of the low frequency transducers as they are mounted within the cabinet. An equalizer is placed between the amplifier and source of audio content for canceling the complex pole of the low frequency transducers and for establishing a new complex pole as a cut off point in which no low frequency sound would be generated by the low frequency transducers.

Description

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a side cut away view of a typical woofer cabinet and enclosed low frequency transducers which can be employed in benefiting from the present invention.

FIGS. 2A and 2B are electrical equivalent circuits of the woofer assembly of FIG. 1 in free air (FIG. 2A) and in a sealed cabinet (FIG. 2B).

FIGS. 2C and 2D correspond to FIGS. 2A and 2B, respectively, showing a graphical equivalent of the relationship between the output or response (dB) and frequency of woofer systems.

FIG. 3 is a block diagram of the equalizer system made the subject of the present invention.

FIGS. 4A and 4B are schematic layouts and graphical depictions of the equalizer system shown in FIG. 3.

FIG. 5 is a graphical depiction of the relationship between woofer output (dB) and frequency showing the effect of the equalizer system shown in FIGS. 3 and 4.

Claims

1. A method of optimizing the low frequency audio response emanating from a pair of low frequency transducers housed within a cabinet, said low frequency transducers being electrically connected to a power amplifier and source of audio content, said method comprising characterizing the resonant frequency (Fs) and amplitude (Q) of the high-pass pole of the low frequency transducers as they are mounted within said cabinet, placing an equalizer between said amplifier and source of audio content, said equalizer canceling the complex pole of the low frequency transducers and establishing a new complex pole for establishing a lower cut off frequency below which the output generated by said low frequency transducers diminishes.

2. The method of claim 1 wherein said pair of low frequency transducers are physically mounted in a closed cabinet in opposition to one another.

3. The method of claim 1 wherein said pair of low frequency transducers are physically mounted in separate closed cabinets in opposition to one another.

4. The method of claim 1 wherein said pair of low frequency transducers are wired electrically in parallel with one another.

5. The method of claim 1 wherein said pair of low frequency transducers are wired electrically in series with one another.

6. A method of optimizing the low frequency audio response emanating from a low frequency transducer housed within a cabinet, said low frequency transducer being electrically connected to a power amplifier and source of audio content, said method comprising characterizing the resonant frequency (Fs) and amplitude (O) of the high-pass pole of the low frequency transducer as it is mounted within said cabinet, placing an equalizer between said amplifier and source of audio content, said equalizer canceling the complex pole of the low frequency transducer and establishing a new complex pole for establishing a lower cut off frequency below which the output generated by said low frequency transducer diminishes.