Digital Processor Reviews

Spectral is a bit of an enigma in the high-end audio world. Although nearly 20 years old and one of the founders of the American high-end audio industry, Spectral isn't a name that comes quickly to mind when considering the best of the best in high-end.

Spectral's low profile is of their own choosing. They advertise very little, their products are demonstrated in a small number of stores, they almost never send products to magazines for review, and they are very quiet about their accomplishments.

At the 2019 AXPONA, I took part in one of my first official meetings, as editor of Stereophile, with members of the manufacturing community: the German company T+A. They were presenting in the room of Texas dealer Lone Star Audio, which was owned by the late Jim Hench. They had a corner hallway to themselves: two rooms and, at the time when I arrived, a hallway table brimming with coffee and pastries. Fortuitous timing.

This unique device is a solution to a problem that previously couldn't be solved.

There are, of course, any number of little boxes that can extract audio from the HDMI video bitstream; they began to appear on the market to fill a need for a way to route audio from a player's HDMI output In the recent past, you could buy a good-quality—even audiophile-grade—universal player and listen to SACDs via its good-sounding analog outputs. But good-sounding universal players are becoming scarce.

In an era when polar opposites compete as absolutes, it can be a challenge to acknowledge the different and equally valid ways in which audiophiles approach musical truth. But the reality is that our perceptions of how reproduced music should sound are determined, to a large extent, by how we approach the live experience.

Even as digital/analog processors were becoming a hot product category in the early 1990s, audiophiles were also learning that timing uncertainties in the AES/EBU and S/PDIF serial datastreams—jitter—would compromise any improvement in sound quality offered by these DACs. Some companies therefore introduced products to reduce or eliminate jitter—in the November 1994 issue of Stereophile, Robert Harley reviewed three such products: the Audio Alchemy DTI Pro, the Digital Domain VSP, and the Sonic Frontiers UltrajitterBug. I still have Stereophile's review samples of the UltraJitterBug and VSP, along with two contemporary DACs: a PS Audio UltraLink and a Parts Connection Assemblage DAC-1.

As our reviews of these products were published before Paul Miller's and the late Julian Dunn's development of the "J-Test" diagnostic signal, I performed J-Test jitter measurements to bring that 1994 review into the 21st Century. You can see what I found here.

Making digital audio sound good appears to be a much more difficult job than its developers first realized. When digital audio was in its infancy, there was a tendency to think that digital either worked perfectly, or didn't work at all. This belief led the engineering community to devise ill-considered and flawed standards that affect the musical quality of digitally reproduced music today.

Unlike the world of recorded music, where streaming has decimated sales of physical products, book publishing is seeing the reverse trend: sales of eBooks are declining while those of both hardback and paperback books are recovering. I have been a book junkie all my life—the two long walls of my listening room are lined with floor-to-ceiling bookshelves and I have many boxes of books in storage—but these days almost all my book reading is with the Kindle app on my iPad mini.