Motorola 56000

A DSP chip that never sat still in a rack — it turned up in restoration suites, radio automation, and sampling workstations.

Overview

The 56000 is a Motorola digital signal-processing chip, and the honest way to describe it is by where it actually ended up: inside other people's equipment. The period record doesn't give the 56000 a spec sheet of its own — no clock speed, no word length, no pinout — but it does show the chip doing real work across a surprising spread of gear, from a Macintosh II audio card to a radio newsroom automation system.

One of the more telling placements is Southworth's Max Audio line for the Macintosh II NuBus system. Three cards used the 56000, and the split of duties says a lot about the chip's role: an analog card handled all A/D and D/A conversion with a 20-bit proprietary converter, a Quad 56000 DSP card took on reverberation, effects, frequency-domain processing, sample playing, and additive synthesis, and a Digital Audio/SMPTE card moved AES/EBU data while reading and generating SMPTE time code. That's a lot of responsibility riding on a single processor family, and it's the sort of architecture that only makes sense when the DSP is fast enough to be trusted with the conversion and effects chain at once.

Peavey leaned on the 56000 just as heavily. The DPM 3 SE Composition Center, the deluxe version of Peavey's DPM 3 workstation, ran its software-based architecture on three 56000-series chips and sampled at up to 48kHz/16 bits. Whether that counts as a workstation or a synthesizer depends on your definition, but the chip count tells you Peavey wasn't treating the 56000 as an afterthought.

The MediaMatrix card pushed the count higher still. Peavey's MediaMation system mounted a MediaMatrix DSP card inside a PC and ran five 56000 processors per card, with the number of cards limited only by available slots. The operating software let a designer pull individual signal processors onto the screen, draw the audio chain as a block diagram, and wire the blocks together with a mouse. Audio (January 1997, p.65) presented the B&K Components AVP1030 as the heart of a high-end home theater mere mortals could afford, part of the same era of DSP-driven audio gear.

Restoration work is where the 56000 earned its most serious reputation. Sonic Solutions' NoNOISE, devised by Andy Moorer, was a toolbox of signal-processing programs rather than a single box, and it ran on machines equipped with Motorola 56000 DSP chips and large hard-disk storage. Recording Engineer framed the system as an "after-the-fact" treatment for old recordings — a way to increase signal clarity on material that was already committed to tape or disc. The same article traced the idea back to Dr. Tom Stockham's late-1970s deconvolution work on Caruso recordings at Soundstream, which required measuring a recording horn's impulse response and applying an inverse digital filter. NoNOISE was the commercial descendant of that thinking, and it needed a DSP with enough headroom to run the filters.

Broadcast automation rounded out the picture. Radio Computing Services' ProSonix digital editor/workstation, part of the RCS Works package, was based on the 56000 and offered AES/EBU I/O, waveform editing, automated mixing, and time compression/expansion in stereo or 8-track form. Scott Studios and Arrakis were pushing their own automation systems in the same period, and the 56000 sits in that ecosystem as the processing engine under the editing and playback features rather than as a headline component.

What the record does not give is the chip's own datasheet — no clock rate, no instruction set details, no package type, no production years. Collectors chasing a bare 56000 should expect to find it as a socketed part inside a Southworth card, a Peavey workstation, or a broadcast rack rather than as a standalone showpiece. The cards and workstations are where the 56000's story lives, and the period coverage treats it as the enabling silicon behind a generation of digital audio tools rather than as a product in its own right.