Motorola 56009 DSP Processor
A 24-bit, 80 MHz workhorse that ended up decoding Dolby Digital in a dozen different black boxes, and almost never under its own name.
Overview
The 56009 never had a face. It sat inside other companies' products and did the heavy lifting, and the badge on the front panel got the credit. Collectors who pull the lids off late-nineties A/V preamps and surround processors keep finding the same part number: a 24-bit, 80 MHz Motorola DSP from the 56000 family, usually working as the Dolby Digital decoder.
The products that used it show what the 56009 actually did. B&K Components built its AVP1030 preamp/tuner/processor around the chip. Its own advertising called the AVP1030 "the first Dolby Digital (AC3) preamp tuner/processor powered by the Motorola 56009 DSP processor." That same advertising billed B&K as an "Alpha development site" for Motorola's 56000 Series - a partnership in which B&K helped design, develop, and test the newest processors.
Krell followed the same pattern. It put a 24-bit, 80 MHz Motorola DSP-56009 in its surround processor and, per Audio (December 1997, p.106), claimed the chip delivered 20 dB better signal-to-noise and an order-of-magnitude reduction in harmonic distortion compared to what came before. The same review singled out the Krell's Dolby Digital playback as producing "the cleanest upper midrange" the reviewer had heard from the format. Whether the credit belongs to the chip or the analog design around it is a fair argument. The 56009 was the common part.
Three of them. The chip was cheap enough to multiply and fast enough to justify it. The AVC-2500 handled Dolby Digital, DTS, Dolby Pro Logic, and Home THX Ultra processing, and the review's verdict was that it delivered excellent stereo and very high-quality surround for a price that wouldn't make anyone gasp.
The 56009 wasn't a dedicated Dolby part. It was a general-purpose DSP that manufacturers wired up to whatever decoding job they needed done. Kenwood's VR-2090 A/V receiver used separate 24-bit Motorola 56009 chips to decode Dolby Digital and DTS, with a third Motorola chip (a 56007) handling bass management and the ambience modes. The 56009 count in that receiver was two.
The chip also turned up well outside the home theater rack.
The 56009 is a component, not a product. There is no Motorola-branded 56009 box to hunt down. The way to own one is to buy a B&K AVP1030, a Parasound AVC-2500, a Kenwood VR-2090, a Krell surround processor, or a Quantec Yardstick. Documentation is thin, and the chip's reputation lives mostly in the service manuals and magazine reviews of the equipment it powered.
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