Reference

The end of two audiophiles' friendship:

"My system has great imaging!" "I can hear sound coming from beyond my speakers." "The depth image in my system goes back at least 20 feet." Yes, we audiophiles are proud of our imaging (footnote 1), and we've worked hard to get it. My back is still aching from the last time I tweaked my speakers until the image was just right.

Editor's Note: One-bit DAC chips in the 21st century, where the analog output signal is reconstructed from a very high-rate stream of pulses, are ubiquitous. But a quarter-century ago, those chips were only just beginning to stream from the chip foundries. In this feature, we aggregate Stereophile's 1989 coverage of the then-new technology, starting with Peter van Willenswaard on the basics.—John Atkinson.

1989 may well become the year of the D/A converter (DAC). CD-player manufacturers have, almost without exception, launched research projects focusing on this problem area of digital audio; many of these projects are already a year old. This is, however, by no means the only imperfection keeping us away from the high-quality sound we have come to suspect is possible with digital audio media, and maybe not even the most important.

In a recent answer to a reader's letter, I somewhat bluntly stated that Stereophile's reviewers use "hi-fi" adjectives to describe loudspeaker sound because even good loudspeakers are too far removed from sounding "real" to be compared directly with live music. Upon reflection, this may have sounded too dismissive, so I will elaborate a little in this short essay.

When I decided to write a piece on the subject of concert-hall acoustics, I realized that almost all discussion concerning this topic is based on the viewpoint of the listener in the audience. While this is important (since the primary purpose of any hall is to bring audience and performance together), the criteria that musicians employ in concert-hall evaluation address sonic parameters that are probably not obvious to the casual listener, and may often be at odds with conclusions reached from the other side of the footlights. Some readers might feel that any discussion of concert halls has no place in a publication such as Stereophile; they may have a point, especially if their sole aim through audio is to produce sonic spectacle, rather than to recreate an artistic event. I believe, however, that there are some readers who would like to gain some insights into the specific problems and acoustical considerations presented to performing musicians, and possibly come away with some fresh ideas to incorporate in their listening criteria.

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.

The main inherent advantage of the full-range electrostatic loud speaker system is that it allows a single diaphragm to embody the conflicting attributes needed for optimal performance at both extremes of the audio range. Its thin-membrane diaphragm can be made exceedingly light, for superb transient response and extended HF response, yet it can be about as large in area as desired, for extended LF response.