Abstract: A method, circuit and article of manufacture for restoring high-frequency content in a first signal includes down-sampling the first signal by a factor to give a second signal; up-sampling the second signal by the same factor to give a third signal; low-pass filtering the third signal to give a fourth signal; high-pass filtering the fourth signal to give a fifth signal; and, adding the fifth signal to the first signal.

Abstract: A method for optimizing multiple psychoacoustic effects in a sound system includes synthesizing a high-frequency restored version of a input signal; adding the high-frequency restored version of the input signal to the input signal to create a second signal; synthesizing a third signal having enhanced spatialization from the second signal; synthesizing a fourth signal having virtual bass from the second signal; and, adding the third and fourth signals, or second, third and fourth signals, together to create an output signal.

Abstract: A method of performing an infinite-impulse response digital filter includes switching address pointers between a first instance of the filter and a second instance of the filter; where the first and second instances represent the same filter. A first instance of the filter executes operations sequentially multiplying a current input data value, and first and second previous input data values, with corresponding ones of a first set of filter coefficients, using a multiplier; and a second instance of the filter executes operations sequentially multiplying first and second previous intermediate data values with corresponding ones of a second set of filter coefficients, using the multiplier. Switching between first and second instances of the filter occurs at each data input value or frame according to an alternating signal.

Abstract: A method for spatialization using stereo decorrelation. The method generates decorrelated left and right signals by filtering the left input channel using an all-pass filter with a first group delay and filtering the right input channel using an all-pass filter with a second group delay; the second group delay being different than that of the first group delay. The decorrelated left signal is subtracted from the decorrelated right signal to create a second left signal and the decorrelated right signal is subtracted from the decorrelated left signal to create a second right signal. The method generates a side signal by adding the filtered left input channel signal and the filtered right input channel signal. The side signal is added to the second left signal to generate a left output signal the side signal is added to the second right signal to generate a right output signal.