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Colloms on Cables

Underpinning a discussion about the merits of potentially costly specialist audio cables is an obvious question: Why do we need them? Doesn't almost all wire conduct audio signals with negligible distortion and very little loss of power? Specialist hi-fi cables seem expensive for what you get. Especially at the upper end, they seem like a worse value than electronics and loudspeakers. Depreciation is greater, too: Cables are almost a consumable.


But if you wish to finesse the quality endeavor of classic separates-based hi-fi systems, you cannot do without them. Fundamentally, it is not the efficient transfer of audio power that's the issue; that is the easy bit. Rather, it is a matter of optimizing the transmission of the more subtle information that describes recorded acoustic, instrumental detail, the performers, and, not least, dynamics and rhythm: Are your feet tapping unconsciously in time to the performance?

NWAA Labs: Measurement Beyond The Atomic Level

The setting is surreal. As you drive into the Satsop Business Park in rural Elma, Washington (pop. 3500, max), eyes immediately fixate on the looming 481'-tall cooling towers of an abandoned nuclear facility. Remnants of the largest nuclear power plant construction project in the United States, the site was mothballed in 1983, in part due to concerns triggered by reports of what had happened at Pennsylvania's Three Mile Island four years earlier.

Book Review: Designing Audio Power Amplifiers

Designing Audio Power Amplifiers, Second Edition, by Bob Cordell, Routledge/Focal Press, 2019. 776pp. $160.00, hard cover; $97.95, paperback.


I first met Bob Cordell at clinics he gave at the last audio show Stereophile organized, Home Entertainment 2007, in Manhattan. At those clinics, Bob shared his views on why amplifier measurements are not always good at predicting differences in sound quality. So when I was scheduled to host a seminar—"Amplifiers: Do Measurements Matter?"—at this year's now-canceled AXPONA, Cordell was on the short list of designers I felt would offer valuable insight.

Going Dutch (& Dutch): a Conversation with Martijn Mensink

In his review of the three-way, active Dutch & Dutch 8c loudspeaker in the August 2019 issue of Stereophile, Kalman Rubinson concluded that "The D&D 8c demonstrates that active, DSP-empowered speakers are the future." I was equally impressed by the 8c's measured performance—a superbly flat on-axis response and an unmatched control of dispersion over the entire audioband—and asked to borrow a pair so I could experience the speakers in my own listening room.

Book Review: High Performance Loudspeakers, Seventh Edition

High Performance Loudspeakers: Optimising High Fidelity Loudspeaker Systems, Seventh Edition, by Martin Colloms. John Wiley & Sons, Inc., 2018. Paperback, 696 pp., $95. Available as an eBook, $79.99.


"Listen to that—that's what I mean by 'cone cry!'"


It was 1979. I'd been taking part in a blind listening test of loudspeakers organized by Martin Colloms (footnote 1) for the British magazine Hi-Fi Choice and, after the formal sessions had ended, had asked Martin to explain something I'd heard. A drive-unit's diaphragm produces cone cry when it resonates at a frequency unconnected with the musical signal it is being asked to produce; we had been using an anechoic recording of a xylophone, and one of the loudspeakers we'd been listening to was blurring the pitches of some of the instrument's notes.

Blind Listening at Harman International

Revel began demonstrating prototypes of the Performa F228Be, reviewed elsewhere in this issue, at the Consumer Electronics Show and other audio events in 2015, though they had yet to settle on the model name. The most salient feature that distinguished the F228Be-to-be from the established Performa3 F208 was the new beryllium tweeter, and while it sounded more than okay under show conditions, I always heard a bit of brightness and harshness. I knew it was still a work in progress, but I wasn't very eager to want to take it home.

Power According to Pass

Virtually all of the active components in your system—DACs, preamplifiers, power amplifiers—work by modulating the DC output of their power supplies with an AC music signal. Surely, then, the more perfect your household AC is, the more perfect your audio system's output will be. Analogies abound—to dirty water used in distilling good whiskey, to inferior thread used to weave fine fabrics—and all amount to the same thing: you can't make a silk purse out of a sow's ear.

Zen & the Art of A/D Conversion

In a series of recent feature articles for Stereophile, Jim Austin has examined how the controversial MQA codec works: "MQA Tested, Part 1," "MQA Tested Part 2: Into the Fold," "MQA Contextualized," "MQA, DRM, and Other Four-Letter Words," and, most recently, "MQA: Aliasing, B-Splines, Centers of Gravity." I doubt there is a Stereophile reader who is unaware of the fracas associated with MQA, and I have been repeatedly criticized on web forums for describing its underlying concept as "elegant."


But elegant it is, I feel.

MQA: Aliasing, B-Splines, Centers of Gravity

The right thing at the wrong time is the wrong thing.—Joshua Harris


The sampling theory formulated by Claude Shannon in the late 1940s had a key requirement: The signal to be sampled must be band-limited—that is, it must have an absolute upper-frequency limit. With that single constraint, Shannon's work yields a remarkable result: If you sample at twice that rate—two samples per period for the highest frequency the signal contains—you can reproduce that signal perfectly. Perfectly. That result set the foundation for digital audio, right up to the present. Cue the music.

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