On CD Quality…

By Bryan Geyer

Bob Widlar, the Genesis

When partners Sony and Philips initially teamed to develop the compact disc (1979) and the first CDs came to market (in early 1983, in the U.S.), the unveiling was widely hailed as the arrival of “perfect sound forever”. That infamous quote has long been derided by persistent doubters, and there have been plenty of hiccups en route, but much of the best unbiased opinion of today concludes that the Sony/Philips claim was effectively prescient, although premature. Assuming good playback mechanics and modern decoding technology, standard Red Book CDs are now aurally indistinguishable from the finest high resolution means of digital recording extant. While a select set of audiophiles might still dispute that opinion, and contend that some favored hi-rez digital streaming process presents audible advantage, their collective criticism has shriveled. Today, with obviously increasing consistency, dedicated audio connoisseurs concur that, finally, there’s little or no detectable difference between standard Red Book CD audio quality and the best of the other alternatives. Any aural quality gap, if such exists at all, is now too trifling to merit recognition when it comes to human perception.

What accounts for this evolutionary improvement in CD sound quality? Well, just as in the case of so many other things, there’s likely no one single reason. It’s probably the culmination of a lot of learning, adjustment, and adaptation—plus dramatic improvement the accuracy of the monolithic integrated circuit chips that comprise all modern digital-to-analog converters (DACs). Here’s my take…

Listening habits…

When CDs were initially introduced, listeners were quick to appreciate the improvement in background noise, but many didn’t know how to handle the enhanced dynamic range to best advantage. This certainly happened to me! In 1987, I already owned an LP recording of the original Perlman/Giulini  performance of the Beethoven Violin Concerto, and when I compared it to the new CD release of the same performance, I judged the CD sound to be inferior; it seemed subdued. I later realized that this was because I had listened at about the same peak volume levels as set for the LP record. When I later advanced the volume to boost the quiet passages of the CD to more nearly match the LP’s quiet parts, the CD sound came alive; the enhanced dynamic range was then apparent. It took me a while to adjust to this asset. Even today, I think that lots of listeners persist in setting “sub-natural” CD volume levels. This tendency is further driven by the compulsion to reduce the listening level when bombarded by pop-market CDs that are mastered with compressed peaks (to yield consistently loud sound). That’s a stunt that can’t be done when mastering to vinyl, and might account for the vinyl preference that some listeners profess when they compare a popular LP record with its CD equivalent. Thankfully, this intentional compression of the signal is confined exclusively to the making of “pop market” CDs, where the “mobile market” dominates, and where loud equates with better. Classical music CDs have never been mis-mastered in this same corrupt manner.

Learning curve priorities…

Early phase CDs that trace to the mid/late 1980s were often inconsistent. Mixing and mastering techniques were in flux, and conversion accuracy didn’t meet what’s available today*. Progressive improvements in recording technology evolved throughout the mid-’90s and into the ensuing decade, buoyed by improved methods of test and measurement. This progress was probably slowed by the attendant clamor to create higher density storage when emphasis was diverted to focus on various forms of compression, e.g. MP3 (1993) + its derivatives (1995, 1998, 2008). Regardless, the decisions and commitments that Sony and Philips made in the beginning have ultimately proved correct. Forty year foresight in the field of consumer technology is rare, but these two companies were uniquely capable, with superb engineering staffs, visionary management, and a strength of conviction seldom seen in corporate environs. It’s accurate to say that what they promised has been achieved.

Conversion accuracy…

Major advances in monolithic semiconductor manufacture, especially with respect to the “on board” integration of symmetrical differential linear topology, has progressively boosted the performance of audio frequency DAC chips. Designs that were once considered challenging are now churned out on bigger wafers, with better test yields. These current generation chips can provide standard Red Book CD sound quality that’s fully consistent with the limits of human perception, and do so at costs that make it feasible to use them in a wide variety of consumer-level gear. Their application in the high performance audio products market has been pervasive in the course of the recent decade.

CD access…

While it’s convenient to access CD quality via Tidal streaming, that means is somewhat better suited to popular music. Cloud shopping for classical selections can get complex; maybe even messy. Your personal nature, and the music genre involved, will largely decide how you elect to build your own private music library. My overwhelming preference is to buy and own the physical CD, rather than pay for periodic access. I vastly prefer having the disc in hand. But I always listen only at home—I’m not into mobile listening—and I utilize headphones only in the bedroom, and only for audio books.

Those who express serious interest in playing CDs at home will need a good player and a modern DAC. The latter can be either self-contained, inside the CD transport, or provided as a separate external box. Top quality converters are available both ways, and an external DAC isn’t inherently superior. In my experience, “good” CD players start in the vicinity of ~ $1,500 and go upward. The cheaper players are just not consistently reliable. A really good CD player should provide long problem-free service life, smooth and responsive control options, quiet operation, and a relatively modern DAC. Stick to single disc players. There are no existing multi-disc CD players that I can personally recommend at this time, and the play time (to 80 minutes max.) of a CD is such that one-at-a-time feeding is appropriate. Use an FM tuner source if you want background fill. Used CD players are obviously high risk, and they might not utilize a modern DAC.

The vinyl alternative…

…is a grossly inferior substitute. Refer…https://classicalcandor.blogspot.com/2019/07/on-considering-vinyl-revival.html.

BG (January 2020)

*Monolithic operational amplifiers have become a vital component in the evolution of high performance DACs. The world’s first op amp chips (µA702, µA709) appeared in the mid-1960s, as devised by linear design genius Bob Widlar, a brilliant eccentric who was then at Fairchild Semiconductor. Intensive development and improvement followed throughout the 1970s and into the mid-’80s. Later emphasis was devoted to advances in symmetrical integration, shrinking topology, increases in wafer size, and yield enhancement. All of the high performance DACs made today utilize this late phase linear technology. The level of excellence that’s been achieved in the past 15 years exceeds anything previously envisioned, and current OEM selling prices make these op amp chips practical for use in almost any consumer market electronic product.