A Development System for Real-Time Digital Audio Signal Processing

Abstract

This article describes a commercial digital audio signal processor, the Eventide SP2016 (Fig. 1), together with a software development system that makes it possible for users to create their own realtime signal processing programs. The SP2016 is a general-purpose signal processor that is optimized for time-domain applications. It features two separate 16-bit analog-to-digital and digital-to-analog (ADC and DAC) channels to enable complete stereo operation at a full signal bandwidth of 16 KHz. As a stand-alone unit designed for professional recording studios, sound reinforcement, and electronic music applications, it does not require an external computer controller. All features can be operated from the front panel of the unit or from a hand-held remote control. Factory programs stored in erasable, programmable read-only memory (EPROM) are provided with the unit to perform many types of as well as delay, flanging, chorusing, filtering, loop editing, and other special effects. We discuss the architecture of the SP2016 and particularly its high-speed array processor and then describe the arithmetic-logic unit (ALU) assembly language and SPUD high-level language used to write SP2016 signal processing programs. We include as a programming example a simple reverberator with RT60 control. (RT60 refers to the it takes for to be 60 db down from its initial level. It is thus a way of saying reverberation time in a more precise way.) Finally, we describe the SPUDsystem development system, a portable software tool that can be used to create SP2016 programs. System Architecture