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Not even close

First there is a blatant error:

"Since its introduction in 1995 the original PMD-200 HDCD digital filter software has been the choice of high-end digital audio designers for their most ambitious processors and players. This was no accident. Digital designers in most high-end companies recognized the unrivaled performance of the PMD-200."

This is utter nonsense, which is why it isn't on the Spectral website.

The truth is that the PMD-200 never made it to production. It was a special version of one of the Motorola DSP chips that came pre-programmed with both HDCD decoding and the digital filters developed by the HDCD team.

The reason for its existence was because Pacific Microsonics had invested heavily in making an ASIC (custom IC) for the PMD-100, the original HDCD decoding digital filter. It costs around $500,000 to have a custom IC made. But it was made on a 0.6 micron process. After about five or six years, the foundry shut down that line as it wasn't making enough money for them. Pacific Microsonics was never as profitable as the founders had hoped for and they didn't have another $500,000 to make another custom IC.

So instead they used the fact that general purpose audio DSP chips had gotten cheaper to migrate the whole thing into a Motorola DSP platform (I forget which one now.)

But the whole thing unraveled pretty quickly after that. Motorola spun off the DSP chip division as "Freescale" to concentrate on cell phones (one of the perils of being a publicly-held company that has to have 10% growth per quarter or face the wrath of the stock market). Pacific Microsonics wasn't profitable enough to survive and were probably relieved to find a buyer -- Microsoft.

Microsoft didn't want to dick around selling chips to nutty high-end companies. So the PMD-200 never made it to full production. There were a handful of companies that used it. The most obvious example was the Assemblage DAC (a division of Sonic Frontiers, that also went belly-up shortly thereafter). There are very few of those DACs in existence.

The only other model that I am aware of is one of the Cary disc players. They claimed to use a PMD-200 years after it was discontinued. I don't know if they found a stash of chips somewhere or were copies. (All of the Cary disc players were made in China according to one fairly recent post.) It would be tough to copy the PMD-200 without the source code. But you can still buy it from Microsoft for $10,000 if you want to.

Bottom line is that the article starts out on the wrong foot.

The rest of the article basically says that the Spectral filter has more taps than most filters do. Nothing about minimum phase or pre-ringing.

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