Correction circuit and method for improving the transient behavior of a two-way loudspeaker system

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Described herein are the transducers, correction circuits, a crossover circuit and cabinet geometry for a multi-way loudspeaker system; also described are methods for integrating these circuit components with reduced system errors as compared to the above-defined ideal loudspeaker system.
More specifically, different forms of correction are described which, used together, reduce system error.
These forms of correction fall into three general categories: 1.
Transducer correction in the loudspeaker cabinet; 2.
Composite system corrections at an on-axis measurement point; and 3.
A phase offset to increase the beamwidth in which flat amplitude and linear phase responses are achieved.
In the first category, the described transducer correction includes the addition of constant delay to the signal of either the high or low transducer by a fixed phase correction circuit.
This is done so that the acoustic centers of the high and low transducers are made to align in a plane parallel to the front panel of the speaker box.
Also included is correction for flat amplitude and linear phase responses in both the individual high and low transducers.
Correction is done over the transducer's operating frequency ranges and in the case of amplitude correction is done by tunable correction circuits, and in the case of phase correction by fixed phase correction circuits.
The second category of correction, the composite corrections, include inserting a crossover circuit to divide the audio signal into a high and low frequency band, correction to achieve flat composite amplitude response by a tunable amplitude correction circuit, and correction for linear composite phase response by fixed and tunable composite phase correction circuits.
Because of interaction between circuits, also described is the need to iteratively repeat the amplitude and phase correction steps for the composite response.
Finally, a phase offset technique is described for providing relatively flat amplitude and linear phase responses over an increased vertical beamwidth