The present invention relates to audio signal processing, and more particularly to methods and apparatuses for emulating and controlling various features of mechanical spring reverberation in a digital audio processing system. According to certain aspects of the invention, such an emulation is performed so as to enhance or alter the characteristics of a digitally stored or processed audio signal in substantially the same manner as a mechanical spring reverberation system. In one example embodiment, the propagation of energy through a mechanical spring is simulated using dispersive waveguides, wherein left-going and right-going waves are separately processed, and the effects of dispersion and attenuation commuted to the waveguide ends. According to additional aspects, many spring reverberators contain spring elements arranged in parallel, with no coupling between springs. Accordingly, in another embodiment of the present invention, such reverberators are modeled using a set of waveguide structures, arranged in parallel, and tuned to simulate the dispersion and attenuation of the torsional propagation modes of each of the individual spring elements. According to further aspects, reverberators occasionally have spring elements comprised of spring segments connected in series. Accordingly, in yet another embodiment of the invention, such arrangements are emulated using dispersive waveguide structures with scattering junctions between modeled spring segments. According to still other embodiments of the invention, both longitudinal and torsional waves are simulated so as to produce a widening over time of successive arrivals at the simulated pick-up, to thereby account for the difference in propagation speed between the torsional and longitudinal modes.