One of the great imponderables in hi-fi is how much the vibrations of a dynamic loudspeaker's cabinet walls contribute to its overall sound quality. Studies by William Stevens in the mid-1970s showed that, with some speakers, the acoustic output of the enclosure could be almost as much as that from the drive-units. Since then, responsible speaker designers have worked hard either to damp cabinet vibrations or to shift them to higher frequencies where their effect on the music will be less deleterious.
In recent years, computer modeling, finite-element analysis, and laser interferometry have brought about a huge increase in our knowledge about what makes the moving-coil loudspeaker drive-unit work. Nevertheless, it has remained fundamentally unchanged since it was invented by Rice and Kellogg more than 60 years ago. That doesn't mean that it hasn't been refined considerably; in this review I examine the performance of a design whose drive-unit technology has been taken to the limit of what is currently possible, the B&W Silver Signature.
From London, England, to Santa Fe, New Mexico, is a pretty big jump, both geographically and culturally. From Hi-Fi News & Record Review to Stereophile, however, is a mere hop; the similarities overwhelm the differences. Unlike the US, mainstream magazines in the UK have managed to keep in touch with the fact that hi-fi components sound different; to edit and to write for an ostensibly "underground" American magazine presented no major philosophical problems. (I say "to edit," but as mentioned in "The Big Announcement," Vol.9 No.3, my editing is done in harness with Stereophile's founder and guiding light, J. Gordon Holt.)
I must admit, right from the outset, that I find reviewing electronic components harder than reviewing loudspeakers; the faults are less immediately obvious. No preamplifier, for example, suffers from the frequency-response problems endemic to even good loudspeakers. And power amplifiers? If you were to believe the older generation of engineers—which includes some quite young people!—then we reached a plateau of perfection in amplifier design some time after the Scopes Monkey Trial but well before embarking on the rich and exciting lifestyles afforded us by Reaganomics. (In the UK, it is generally felt by these people that the date coincided with the introduction of Quad's first current-dumping amplifier, the 405, in 1976.)
Following my reports on 13 mainly inexpensive loudspeakers that have appeared in the last four issues of Stereophile, I thought I would give myself a treat this month by reviewing the latest incarnations of a model that has stood the test of time: the two-way Celestion SL600Si...This is a carefully tuned infinite-baffle design, sacrificing ultimate extension for upper-bass and lower-midrange quality. Its crossover is conventionally British in that it puts flatness of on-axis amplitude response ahead of time coherence, while everything about it, from drive-units to the cabinet itself, is flagrantly "high-tech."
When some unknown copywriter coined that immortal phrase to promote the worldwide launch of Compact Disc in late 1982, little did he or she foresee how quickly it would become a term of ridicule. Yes, early CDs and players offered low background noise, a flat spectral balance, and freedom from wow and flutter. But all too often, the music encoded in the "perfect-sounding" pits seemed to have taken a vacation, leading the renowned recording engineer John Eargle to offer, in the medium's defense, that if you were to hear just one CD that sounded good, digital technology would be proved to be okay.
"Tonearm?" muttered John Crabbe, my erstwhile editor at Hi-Fi News & Record Review, as he bent over my shoulder some 12 years ago to see what I was writing about. "A tonearm belongs on an acoustic gramophone—you should use the term 'pickup arm,' which doesn't suggest that the arm has a sound of its own."
Back in the spring of 1990, Stereophile introduced its first Test CD, featuring a mixture of test signals and musical tracks recorded by the magazine's editors and writers. Even as we were working on that first disc, however, we had plans to produce a second disc which would expand on the usefulness of the first and feature a more varied selection of music. The result was our Test CD 2, released in May 1992.
Back in the summer of 1968, I bought a secondhand pre-CBS Fender Precision Bass guitar for the grand sum of £35 (then about $75) (footnote 1). It was so cheap because the previous owner had pretty much scratched the sunburst finish to ribbons. The P-Bass may have looked like roadkill but it played like a dream, so I decided to refinish its body. Paint stripper removed the remains of the original nitrocelloluse lacquer, leaving me with a white wood body—ash, I understand—which I carefully sanded and stained. Contrary to what you might expect, the finish of an electric guitar does have an effect on the sound, so I thought long and hard about how I was going to varnish the body. I ended up applying thinned gloss-finish polyurethane, which I then sanded, repeating this process some five or six times, using finer and finer sandpaper, until the application of a final coat of varnish gave as close to a mirror-smooth finish as I could get...which wasn't anything near as perfect as the piano-lacquer rosewood finish on the samples of the Monitor Audio Studio 6 loudspeaker that Monitor Audio USA sent for review!
I am puzzled. No, really. I know you find it hard to believe that we sacerdotes of the golden-eared persuasion could ever be perplexed, but I have been pondering the imponderables of ports. Ever since the classic work of Richard Small and Neville Thiele in the early '70s showed how the low-frequency response of any box loudspeaker can be modeled as an electrical high-pass filter of some kind, with the relevant equations and data made available to all, there would seem to be very little reason why all loudspeakers with the same extension should not sound alike (or at least very similar) below 100Hz. Yet after reviewing 20 dynamic loudspeakers (and using 24) in the same room over the last seven months, I am led to the conclusion that speakers vary as much in the quality of their mid-to-upper bass as they do in any other region. A few are dry, more are exaggerated in this region; some are detailed and "fast," most are blurred, with the upper bass "slow" (by which I mean that the weight of bass tone seems to lag behind the leading edges of the sound).