Digital Processor Reviews

It has taken almost three years, but Dolby Atmos is now permeating the music-streaming sites; note that most of the recent Grammy winners are available in Atmos.

Up to now, access to Atmos has been largely restricted to HT hardware; its success for music will depend on wide availability and non-HT options for audiophile music lovers to stream and to play discs or files in Atmos, especially in lossless versions. Enter the Arvus H2-4D.

Back in the summer of 2009, USB-connected D/A processors that could operate at sample rates greater than 48kHz were rare. Ayre Acoustics had just released its groundbreaking QB-9, one of the first DACs to use Gordon Rankin's Streamlength code for Texas Instruments' TAS1020 USB 1.1 receiver chip. Streamlength allowed the chip to operate in the sonically beneficial asynchronous mode, where the PC sourcing the audio data is slaved to the DAC. But high-performance, USB-connected DACs like the Ayre were also relatively expensive back then, so in the January 2010 issue of Stereophile I reviewed a pair of soundcards from major computer manufacturer ASUS , the Xonar Essence ST and STX, which, at $200, offered a much more cost-effective means of playing hi-rez files on a PC.

No, the $399 price listed in the specification block isn't a misprint. And yes, the Audio Alchemy Digital Decoding Engine v1.0 is indeed a full-function outboard digital processor. And since this is the August issue, not April, you can stop worrying that this review is some kind of joke.

The $399 Digital Decoding Engine is for real.

I don't know much about horses, but I've been given to understand that dead ones don't respond to even the severest beating. In light of that, I'll make only this brief statement—Even with the best playback gear of my experience, I don't derive as much pleasure from CDs as I do from LPs.—and move on to a simpler truth: Regardless of what I think, CD players are still a necessity for most music-loving audiophiles.

The past 12 months have seen some remarkable developments in digital playback. Standards of digital musicality are far higher than they were a year ago, both on an absolute performance basis and in terms of what you get at various price levels. No other component category has seen such tremendous gains in value for money or number of new products introduced. It seems hard to believe that since Vol.13 No.6 (12 issues ago), we've reviewed such noteworthy digital processors as the Meridian 203, Proceed PDP 2, Stax DAC-X1t, Theta DSPro Basic, Wadia X-32, Esoteric D-2, PS Audio SuperLink, and VTL D/A. Each of these converters brought a new level of performance to its price point—or, in the case of the Stax and VTL, established a new benchmark of ultimate digital performance.

Just as these units provided stiff competition for previous products, so too will they come under the assault of improving technology. The art of digital processor design is so young that we can continue to expect further improvements coupled with lower prices as designers move up the learning curve.

Unless something is broken, the bits from your computer will be delivered to your DAC intact; the claim behind three new products I recently listened through is that each can reduce noise within the DAC—noise that could otherwise corrupt the analog signal and thus make our music less musical. This notion is not based on audiophool woo-woo, but on the basic electronics of mixed-signal systems: Although its input is digital data, a DAC's output is subject to all the noise problems of analog circuits.

The increasing prominence of Blu-ray explains why a device to extract audio from an HDMI stream has become necessary. At first, Blu-ray players had HDMI outputs for video and audio, but to speed their adoption, they also sported analog audio outputs to help users who had older AV receivers (AVRs). Bye the bye, those audio outputs were pared off.