Circuit and method for correcting distortion in a digital audio system

An active delay equalizer for correcting for high end phase distortion in a digital audio system, said active delay equalizer comprising

• a signal input and signal output,
• circuit means between said signal input and signal output for adding time delay to audio signals inputted to said signal input,
• said time delay being added by said circuit means substantially at the lower and middle portion of the audio system's operating frequency range such that the time delayed audio signal at said signal output combines with high end time delay introduced by said digital audio system to produce an overall system time delay which is relatively constant over the system's operating frequency range.

An active delay equalizer for correcting for phase distortion in a digital audio system comprising

• cascaded active delay equalizer sections which provide, over the operating frequency range of said digital audio system, a composite time delay which combines with the time delay of said digital audio system to produce an overall system time delay which is relatively constant, said cascaded delay equalizer sections including
• a single pole all pass delay equalizer section providing time delay near DC and at the low end of said system operating frequency range,
• at least two second order all pass delay equalizer sections tuned above the roll off of said single pole all pass section to provide a composite time delay which rolls off at the high end of the system's operating frequency range.