The audio diaspora is split on the subject of bass. Some audiophiles—surely the majority—consider the reproduction of low frequencies purely in terms of the weight and drama it adds to sounds with significant bass content. Others—the generalists—take a much wider view of the significance of extended bass response, noting that an audio system's ubiquitous high-pass filters are unusual in Nature and suggesting that this is one of the factors that separate, at the fundamental level, live sound from its poorer reproduced cousin. When John Atkinson wrote on this subject more than 10 years ago (Stereophile, November 1995, "As We See It"), he quoted a memorable line by Kal Rubinson that encapsulates this latter view: "Something in Nature abhors a capacitor."
In 1977, just as I was about to take my first faltering steps in hi-fi journalism, the UK's Hi-Fi News ran two articles, translated from French originals by Jean Hiraga, that seemed to me and many others to turn the audio world we knew upside down. The second of them, "Can We Hear Connecting Wires?" was published in the August issue and is the better remembered because it introduced many English-speaking audiophiles to the contention that cables can sound different. The earlier article, published in the March issue, was less earthshaking but still an eyebrow-raiser of considerable force. Simply titled "Amplifier Musicality," it was a response to the word musicality being increasingly used in subjectivist circles to describe the perceived performance of amplifiers and other audio components. It was implicit that musicality was a quality not captured by conventional measurement procedures—a lack of correlation that Hiraga's article sought to address.
Wouldn't you just know it. As soon as I decide on a formal regime of measurements to accompany Stereophile's loudspeaker reviews—see Vol.12 No.10, October 1989, p.166—along comes some hot new technology that changes everything. Robert Harley reported in last month's "Industry Update" column how impressed he and I were with the new MLSSA measurement system from DRA Laboratories.
Much as I like the prospect of being able to grunt a heartfelt Je ne regrette rien immediately before expiring, I know there will be too many what-ifs and wish-I-hadn'ts to make that even remotely possible. But here is one missed opportunity that won't flash before me, because John Atkinson has granted me a second chance.
"The large peak at 16kHz reported by Stereophile...was nowhere in evidence...The most probable explanation of this discrepancy is that the [Waveform supertweeter's] very light ribbon depends on the air load for damping, and that load is much smaller in the thin air up there at 7000' in Santa Fe than at altitudes where less lightheaded and scientifically more accountable reviewers dwell." Thus spake Peter Aczel (footnote 1), erstwhile loudspeaker designer and Editor/Publisher of the reincarnated The Audio Critic, a publication that advertises itself as having "unusual credibility among the top professionals in audio."
The introduction in 1982 of the compact disc ushered in the age of digital audio. Audiophiles now have lots of new digital toys and technologies at their disposal, including SACD, DVD-Audio, MP3 players, hard-drive–based CD players, and digital equalization and room correction, to name a few. Videophiles have similarly benefited from digital technology, with an armamentarium that includes high-definition television, DVD-Video, Blu-ray, HD DVD (the latter two still on the horizon), DLP, LCoS, and D-ILA, among others. Action-based films have also benefited from breathtaking, digitally enhanced special effects. Even those of us who still prefer LPs must acknowledge—reluctantly, perhaps—the incredible impact that digital has had on our hobby (footnote 1).
Editor's Note: The matter of whether—and if so, how—speaker cables and interconnects can affect the sound of an audio system has vexed the audiophile community since Jean Hiraga, Robert Fulton, and others first made us aware of the subject in the mid-1970s. Most of the arguments since then have involved a great deal of heat but not much light. Back in August 1985, Professor Malcolm Omar Hawksford Ph.D (of the UK's University of Essex and a Fellow of the Audio Engineering Society) wrote an article for the British magazine Hi-Fi News & Record Review, of which I was then Editor, in which he examined AC signal transmission from first principles. Among his conclusions was the indication that there is an optimal conductor diameter for audio-signal transmission, something that I imagined might lead to something of a conciliation between the two sides in the debate. Or at least when a skeptic proclaimed that "The Laws of Physics" don't allow for cables to affect audio performance, it could be gently pointed out to him or her that "The Laws of Physics" predict exactly the opposite.
If there is one thing I've learned in almost 28 years (ouch) of audio writing, it's that audience reaction is fickle. Sometimes readers will swallow the most contentious pronouncements without indigestion, only to choke on throwaway lines you've invested with little importance. It just goes to confirm that human communication involves senders and receivers, and they aren't always in synchrony.
If you missed Part 1 of this article (Stereophile, January 2005), or it has faded in your memory, here's a résumé. (Readers who recall Part 1 with crystalline clarity, please skip to paragraph four.) The accurate measuring of loudspeakers requires that the measurements be taken in a reflection-free environment. Traditionally, this has meant that the speaker be placed atop a tall pole outdoors or in an anechoic chamber. Both of these options are hedged around with unwelcome implications of cost and practicality. To overcome these and allow quasi-anechoic measurements to be performed in normal, reverberant rooms, time-windowed measurement methods were developed that allow the user to analyze only that portion of the speaker's impulse response that arrives at the microphone ahead of the first room reflection. MLSSA from DRA Labs is the best-known measurement system to work on this principle, and both John Atkinson and I use it in the course of preparing our loudspeaker reviews.
Pick an expletive—one you would normally use to express deep intellectual frustration—but don't vocalize it. Hold it in reserve for a few minutes, letting it simmer to concentrate its intensity. I'll tell you when to let rip.
In the world of digital audio, jitter has been a focus of audiophile attention for well over a decade. It is blamed for many of the sonic ills of which CD and other digital media have been accused. But here's a puzzle: The major source of frequency intermodulation distortion in audio systems—the loudspeaker—has largely escaped such withering inquiry. Why?
Someday we may speak wistfully to our grandchildren about the "golden age" of digital audio when consumer formats (CD and DAT) contained a bitstream that was an exact bit-for-bit duplicate of the original studio master recording—not a digitally compressed, filtered, copy-resistant version whose sound is "close enough" to the original. Digitally compressed formats such as DCC and MiniDisc represent, in effect, a return to the pre-CD era when consumer-release formats were always understood to be imperfect copies of the studio original. Even the most ardent audiophile accepted the fact that LPs and mass-produced tapes did not, and could not, sound as good as the master tapes they were derived from.
High-quality digital audio systems require that all digital interfaces in the signal path exhibit signal transparency. The widely adopted AES/EBU and S/PDIF interfaces have been criticized for a lack of signal transparency; here we (footnote 1) address possible problems with such interfaces and present methods for improving the interface standard.
Until recently, all problems in digital audio systems were blamed on either the analog/digital converters (ADCs) used in mastering or the digital/analog converters (DACs) needed for playback (footnote 1). As the performance of both ADCs and DACs improved, however, a previously unrecognized mechanism for distortion was unmasked: jitter. As we shall see, jitter—or, more correctly, word-clock jitter—can be a significant limitation in the technical and sonic performance of digital audio systems (footnote 2).