Reduced-memory reverberation simulator in a sound synthesizer

DETAILED DESCRIPTION In accordance with the present invention, a sound or music synthesizer includes a reverberation simulator having a substantially reduced volatile storage, random access memory, or buffer size in comparison to conventional reverberation simulators by decimating the sound signal prior to applying the sound signal to a reverberator and then interpolating the sound signal generated by the reverberator to restore the sample frequency.
The substantial reduction in buffer size enables the usage of the reverberator in low-cost, reduced size and single-chip environments.
In accordance with one embodiment of the present invention, a method of generating a reverberation effect in a sound signal of a sound signal path includes the steps of decimating the sound signal in the sound signal path to form a reduced sample rate sound signal and inserting a delay into the sound signal path to form a reduced sample rate sound signal and a relatively delayed reduced sample rate sound signal.
The method further includes the step of accumulating the relatively delayed sound signal and the sound signal to form a multiple-echo sound signal having a reduced sample rate.
Subsequently, the multiple-echo sound signal is interpolated to restore the sample rate to the sample rate prior to the decimating step.
In accordance with another embodiment of the invention, a sound synthesizer includes a sound signal path for carrying a sound signal and a decimator connected to the sound signal path for reducing the effective sample rate of the sound signal by a decimation factor.
The sound synthesizer further includes a delay line of storage elements connected to the decimator in the sound signal path for generating a sound signal and a relatively delayed sound signal.
The delay line has a number of storage elements reduced according to the decimation factor.
The sound synthesizer has an accumulator connected to the delay line in the sound signal path for accumulating the relatively delayed sound signal and the sound signal, thereby forming a multiple-echo sound signal having the reduced effective sample rate