Robert Harley

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Robert Harley Posted: May 06, 2015 Published: Nov 01, 1991 0 comments
In hindsight, it was inevitable that two sophisticated digital audio technologies—software-based digital filters and Bitstream D/A converters—were destined to be married in one product. The software-based D/A converters offered by Krell, Wadia, and Theta all used multi-bit ladder DACs, and Bitstream-based units have previously relied on off-the-shelf digital filters.
Robert Harley Posted: Apr 17, 2015 Published: Nov 01, 1991 3 comments
"In the fields of observation, chance favors only the mind that is prepared."

When Louis Pasteur uttered these words more than a hundred years ago, he must have speculated that they would apply equally well to future circumstances as to the events of his day. What he couldn't anticipate, however, was the technology to which his insight now seems so appropriate.

Robert Harley Sam Tellig Posted: Jun 18, 2014 Published: Aug 01, 1991 0 comments
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.

Robert Harley Posted: Feb 13, 2014 Published: Mar 01, 1992 1 comments
Since the first digital processor on the market using UltraAnalog DACs appeared (the $12,000 Stax DAC-X1t, reviewed in August 1990, Vol.13 No.8), there has been a proliferation of good-sounding processors using this extraordinary—and expensive—part. Among these are the Audio Research DAC1, Audio Research DAC1-20, VTL Reference D/A, and the groundbreaking Mark Levinson No.30 reviewed last month.
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Peter W. Mitchell Robert Harley Posted: Dec 10, 2013 Published: Dec 01, 1991 13 comments
Editor's Introduction: In 2013, lossy compression is everywhere—without lossy codecs like MP3, Dolby Digital, DTS, A2DP, AAC, apt-X, and Ogg Vorbis, there would be no Web audio services like Spotify or Pandora, no multichannel soundtracks on DVD, no Bluetooth audio, no DAB and HDradio, no Sirius/XM, and no iTunes, to quote the commercial successes and no Napster, MiniDisc, or DCC, to quote the failures. Despite their potential for damage to the music, the convenience and sometimes drastic reduction in audio file size have made lossy codecs ubiquitous in the 21st century. Stereophile covered the development of lossy compression; following is an article from more than two decades ago warning of the sonic dangers.—Editor
Robert Harley Posted: May 21, 2013 Published: Aug 01, 1993 0 comments
The loudspeaker designer's art has changed radically over the past 20 years. Although the goals are largely the same, today's designer employs tools and techniques unimaginable two decades ago. Computer modeling, powerful and affordable FFT machines, and sophisticated new driver technologies are just a few of the advantages enjoyed by the modern designer. The high-tech result is a vastly better loudspeaker—even inexpensive products today are significantly better than those of even five years ago, never mind 20.

The new Genesis III loudspeaker shows just how sophisticated the designer's art has become. The Genesis III is as far removed from the cones-in-boxes loudspeakers of yesterday as a Ford Taurus is from a Pinto. Combining a radically different cabinet with unusual custom drive-units, the Genesis III is a paradigm of how high technology has transformed loudspeaker design.

Robert Harley Sam Tellig Posted: Sep 19, 2012 Published: Sep 01, 1995 0 comments
I can't think of two products at further ends of the audio spectrum than a single-ended triode tubed amplifier and a mass-market Home Theater loudspeaker. Single-ended tubed amplifiers are about reproducing subtlety, delicacy, nuance, and communicating the music's inner essence. Conversely, a Home Theater loudspeaker system—particularly one made by a mass-market manufacturer—would appear to put the emphasis on booming bass and reproducing shotgun blasts, with little regard for musical refinement.

What a bizarre marriage it was, then, to pair the new Infinity Composition Prelude P-FR loudspeakers with the Cary Audio Design CAD-300SEI 11W single-ended triode amplifier (reviewed elsewhere in this issue). This combination didn't happen by accident; as you'll see, these apparently disparate products are a match made in heaven.

I discovered the Infinity Preludes while surveying Home Theater loudspeaker systems for the upcoming second issue of the Stereophile Guide to Home Theater. In addition to evaluating the loudspeaker systems under review with video soundtracks, I assessed their musical qualities—or lack thereof. The Preludes were such a musical standout that I rescued them from the Home Theater room (where they had been powered by mass-market receivers and fed with a laserdisc source) and gave them a new lease on life in the larger music room, with reference-quality source and amplification components. The Preludes' extraordinary musical performance and unique design compelled me to tell you about how they performed in an audiophile-quality two-channel playback system.

Robert Harley Posted: Aug 17, 2012 Published: Mar 01, 1996 0 comments
With the introduction of Audio Alchemy's Digital Transmission Interface (DTI) more than three years ago, the company created an entirely new category of hi-fi product: the jitter filter. The original DTI was a good start, but didn't always improve the sound of the better-quality digital front-ends.
Robert Harley Posted: Apr 27, 2012 Published: Mar 01, 1993 5 comments
There are as many ways of designing a digital-to-analog converter as there are engineers. One approach is to select parts from manufacturers' data books and build the product according to the "application notes" provided by the parts manufacturers. This is the electronic equivalent of a paint-by-numbers kit.

A more creative engineer may add a few tricks of his own to the standard brew. Bigger and better regulated power supplies, careful circuit-board layout, tweaky passive components, and attention to detail will likely make this designer's product sound better than the same basic building blocks implemented without this care. Indeed, the vast range of sonic flavors from digital processors containing very nearly the same parts attests to the designer's influence over a digital processor's sound.

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Robert Harley Posted: Apr 27, 2012 Published: Mar 01, 1993 0 comments
Ed Meitner is one of those rare individuals who charts his own course in audio product design. From his platterless turntable of the mid-1980s to his new Intelligent Digital Audio Translator (IDAT, reviewed elsewhere in this issue), Ed Meitner's products have been distinguished by original thinking and innovative engineering. Although not all his designs have been commercially successful, in each he has attempted to advance the state of the art by rethinking fundamental principles.

Ed is also pursuing an ambitious project that would radically change the way recordings are made. It began when he recorded an electric guitar through a 10" guitar-amp loudspeaker and was dismayed that it was impossible to even come close to capturing and realistically reproducing this apparently simple sound through another 10" speaker. This experience launched his investigation into why reproduced sound is never mistaken for live music, a quest that may result in a radically new recording technique.

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