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.
Most people who now listen to tube amplifiers began with a transistor amp, and know from experience that a tube amp of a given measured power output sounds louder than its nominally identical transistorized equivalent. The unofficial consensus is that you need two to four times the transistor power to achieve the same loudness as you would using tubes. In other words, given the (subjectively) undistorted sound level a 25W (footnote 1) tube amplifier can provide, if you want the same loudness from solid-state technology you would have to replace it with at least a 50W transistor amp (footnote 2).
While the LP-vs-CD debate continues unabated among high-end audiophiles, the rest of the world has already closed the book on the venerable LP. All but a few specialized classical record companies (footnote 1)(and some weird magazines) have ceased releasing new LPs, few record stores sell them any more, and consumers who wouldn't be caught dead owning something that wasn't trendy have long ago dumped their LP collections for cents on the pound.
If you read Stereophile regularly, you already know that all audio equipment does not sound the same. But did you know that a given piece of gear can sound better or worse depending upon how it's set up and used? With a few simple tweaks, you can bring out the best in your audio system.
"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."
Charles Hansen said it best, in a recent e-mail: "People have been holding back from criticizing this technology because they weren't certain that some new discovery hadn't been made." Ayre Acoustics' main man was talking about "upsampling," whereby conventional "Red Book" CD data, sampled at 44.1kHz, are converted to a datastream with a higher sample rate. (Because of its association with DVD-Audio, 96kHz is often chosen as the new rate.)
When the brief flowering of quadraphonics began in the early 1970s, I was still at school. As a nascent but impecunious audiophile, I therefore had a ringside seat at the audio industry's first attempt to go multichannel—and, even for the disinterested onlooker, it wasn't a pretty spectacle.
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."
Though we sometimes take for granted that the basic "language" of our measurements is clear to all of our readers, letters to the editor tell us that this is not the case. Periodically, then, we will attempt to explain exactly what our measurements are and what they purport to show. Though those with technical training may find our explanations a bit simplistic, they're aimed at the reader who lacks such experience.
That was the question asked by a reader who was perfectly happy with his CD-based system. He was using the gain control provided by the variable output of his CD player and was apparently in no need of phono playback or greater flexibility. He asked us to answer this question, ignoring for the moment the obvious functions of switching, volume and tone control, and phono preamplification. With those hardly trivial qualifiers—and bearing in mind the high output available from many of today's line sources, CD players in particular—do you really need the added expense and complexity of a preamplifier?
It has become accepted lore in audiophile circles that the 44.1kHz sampling rate adopted for Compact Disc is too low. Some writers have argued that, as a 20kHz sinewave will only be sampled about twice per cycle, it will not be reconstructed accurately, if at all.