Fidelity Wars!

"CDs are cute. So was the eight-track."

Philips' promise of "perfect sound, forever" is the dream and passion of all who love music and labor to reproduce it beautifully in the home. No goal in audio had been so elusive. Over the past 50 years, fortunes---indeed, lives---have been exhausted in the quest for even reasonably satisfying musical sound. Yet now the commerical leaders in audio would have you believe that you can have perfect sound right in your own living room, conveniently, inexpensively and immedately. Of course, they'll say your music must first be digitally processed. In fact, you, the consumer, no longer have a choice between digital and analog recordings. The vast majority of recordings being released today by the major labels, whether in LP or in compact-disc (CD) format, come from digital rather than analog master tapes.

Digital audio recordings, particularly in the CD format, are spreading across the land. Most industry people are delighted with the market success of the CD. There's gold in those iridescent discs! The ailing record industry's profits are on the rise. Hi-fi-equipment manufacturers and retailers are delighted---sales of CD players are drawing customers back to the showroom. Happy, or at least profitable, days are here again. Some have even proclaimed the LP dead.

In view of the CD's great convenience, seeming indestructibility, better-than-average sound and undeniable "cuteness," it's easy to see why it should succeed. Add to this an unprecedented corrdination of marketing efforts by all the world's major (continued on page 146) Fidelity wars! (continued from page 85) recording and audio-equipment companies, and you have a merchandising triumph. But do you have perfect sound? In the midst of this digital hype and industry coercion, why do some careful listeners continue to extol the virtues of analog sound? Does the LP possess any virtues to justify its continued existence?

An appreciation of the relative strengths and weaknesses of the LP and the CD requires some understanding of analog and digital, two ways in which a musical signal may be recorded and stored. Music is sound, which is a wave phenomenon; and to understand the principles of analog and digital signal processing, we must view sound as waves.

We have all seen wave-form displays dancing across an oscilloscope screen---or at least across our TV screens on late-night reruns of The Outer Limits. When an electrical signal carrying musical information is fed into an oscilloscope, the wave form, which changes with the music's volume and pitch, is shown on the screen. As the music gets louder, the crests of the wave forms get taller; as the pitch gets higher, the wave forms get narrower.

Ideally, in recording music, we want to capture the shape of the wave form exactly as it enters the oscilloscope, without distorting it and without adding noise. Unfortunately, to make matters difficult, most musical wave forms are immensely complex, with several pitches being produced simultaneously by instruments played at different volumes. The resulting wave form would seem to be a chaotic and incomprehensible blur. Throughout our lives, though, we have taught our ear-brain system to unravel that chaos and interpret it as music---as long as the wave form's shape is not too badly altered or masked by noise.

Analog and digital systems handle this complex wave-form information in different ways. Analog strives to follow the wave form exactly. The higher the quality of the analog system, the better it can trace tiny wave-form details without overloading at the same time on high crests. The analog signal may be stored on magnetic tape or in the grooves of an LP record. The analog signal may be stored on magnetic tape or in the grooves of an LP record. The analog approach, which was first used with the Edison cylinders, has evolved to the point where it is capable of astounding accuracy in capturing that wave form. The Achilles' heel of analog, though, is noise, which may take the familiar forms of tape hiss, record pops and ticks, and turntable rumble, to name but three. As genuine improvements are made in analog recordings and playback gear, noise is progressively lowered and the system's ability to resolve more detail on the wave form gets better. This is a great strength of analog: It can be continually improved.

Digital, on the other hand, operates on the assumption that the wave form has to be accurate only up to a point, beyond which no one can hear the differnce anyway. What is to be achieved, however, is the absence of noise. The current digital system, as used in all CDs and most new LPs, captures what it does of the wave form by sampling. When the original digital recording is made, the musical wave form from the microphone goes into the digital recorder's analog-to-digital (A/D) converter. The wave form is then chopped, or sampled, approximately 44,000 times each second. Such a system is said to have a sampling rate of 44K. Each of these samples is then assigned a number, the maximum size of which is called the bit-word length, 16 bits being the current standard. These numbers may then be stored on tape or laser-etched into a compact disc. When the signal is in the form of numbers, it is extremely insensitive to noise and signal loss. This is a real strength of digital. However, because the ear-brain system does not hear numbers as music, playback of the recording requires reconversion to analog by a digital-to-analog (D/A) converter. The D/A converter, with varying degrees of accuracy, reconstructs the wave form and sends it out to playback amplifier and speakers. All audio compact discs conform to this 16-bit/44K system.

Analog may be likened to a photographic print and digital to a lithographic print. Photographic prints are subject to grain, haze, poor focus and color shift. Optimizing all these factors, while hideously difficult, can produce lovely results. Moreover, as finer-grain film, better-quality emulsions and sharper lenses are used, the print quality can always be improved.

Lithographic prints, on the other hand, are created by laying down a regular pattern of dots, the size and density of which may be varied to provide extremely tight processing control and excellent uniformity quickly and inexpensively. However, as practical as lithographic prints are, it is relatively easy to see their dot structure. A lithographic print can be enlarged to provide more detail only up to a certain point. If it's enlarged beyond that point, you don't see more detail, just more dots.

It could be argued that the ultimate lithographic print would approximate a finegrain photographic print. For most print applications, such as popular magazines and newspapers, print-detail resolution doesn't really matter. For critical viewing, however, a standard fixed, coarse line screen would not be acceptable. Imagine your frustration if you could not go to a finer line screen to improve detail because there was a fixed, unimprovable industry standard based on the coarse line. That is essentially the case on with the current, fixed digital standard.

Derrick Henry, writing in the June 1985 issue of Opus, points out the irreversibility of the current digital system: "Whereas the implementation of an analog medium can be imporved without any definite limit, once one has chosed the word length [number of bits] and sampling rate, one has set forever an upper limit to the quality of a digital audio system." In fact, as the quality of the stereo playback system improves, CDs tend to become more disappointing, whereas high-quality analog sources become more satisfying.

Ivan Berger's column in the November 1985 issue of Audio presents and interesting perspective: "Analog builds models, or analogs, of the desired information on the optimistic assumption that our modeling technology is infinitely perfectible ... Digital starts from the cheerful admission that total perfection is impossible, then goes on to assume that we can, by choosing the specific degree of perfection we can live with, achieve it---not approximating perfection but perfecting our approximations ... Digital takes the idea of 'good enough' as its foundation."

The promoters of digital audio would have you believe that the limits or approximations of this system are "good enough" to be considered perfect. It would be nice if they were, because the public is now stuck with this system whether we like it or not.

Just how good is digital?

In spite of the unprecedented industry hype about the CD, there are many who are not enamored of its sound. There is a widely perceived lack of ambience in digital, along with an edgy or unnatural quality to violin overtones. Sounding-board resonances are muted. Delicate high-frequency transients and their overtones are lost in PCM digital recordings. Contrary to popular notion, the musical dynamics of CDs are compressed compared with those of high-quality analog recordings of the same material.

Controlled, rigorous listening tests of recording machines conducted by physicist/concert pianist Jim Boyk at the California Institute of Technology and reported in Science News indicated no superiority of the digital to the analog units. Indeed, in the Boyk tests, there was a general subjective precference for the analog units. Another recent test was conducted by a Sheffield Labs recording team at recording sessions of the Los Angeles Philharmonic Orchestra under the direction of Erich Leinsdorf, as reported in The Absolute Sound. Identical two-channel microphone signals were sent to a variety of analog recording machines, as well as to a JVC digital recorder. Upon careful listening, the consensus was 12 to one in favor of any of the analog recording systems over the digtital recorder. The JVC, by the way, is considered to be one of the best-sounding digital recorders. Edward Rothstein, writing in New Republic, sums it up: "The CD is an immediate, instantaneously impressive achievement, but it cannot be lived with in a sustained musical fashion. In a sound system of sufficient resolution, CDs end up sounding not like perfect sound but like perfectly unreal sound."

Apologists will say that criticisms of digital merely reflect the prejudices of those who cling to the past and to the romance of expensive turntables. But, in fact, most criticisms of digital are based on actual distortions in the system, most of which are unique to digital.

Dr. Roger Lagadec is chief of digital activities at the prestigious Studer/Revox firm in Switzerland, a world leader in the development and manufacture of professional-grade digital and analog recording equipment. The August 1985 Stereo Review quotes Dr. Lagadec as saying, "In Europe the CD was conceived of as a midfi product from the beginning ... I have no argument whatever with those who say that the performance of CD players veries and that the best of CD is lagging a bit behind the best of analog."

What didstortions render the best of digital CD inferior to the best of analog?

The first and most obvious shortcoming of the current system is its sampling rate. Most experts agree that 44,000 times per second is marginal, too coarse. Everyone agrees that a higher rate would be better.

The current 44K sampling rate requires that a drastic filter be used to roll off all information above 20,000 cycles per second. According to an Audio Engineering Society paper written by Dr. Thomas Stockham in 1984, these extremely steep-slope filtering methods, used only in digital, produce peculiar distortions. Although tbeoretically feasible, their sound is too alien to be musically accurate. Current oversampling techniques employed by some CD players only reduce, not eliminte, these problems.

Another side effect of the CD's limited high-frequency response is its relatively slow transient response. In other words, its ability to respond to delicate, quick, high frequencies is audibly and measurably inferior to that of high-quality analog.

Yet another limit to digital's quality is determined by the system's bit-word length. The current word length is 16 bits, which is a pretty big number and would seem to be more than adequate to describe any wave-form sample. But maximum word length is available only at teh loudest musical levels the system can handle. As the music gets softer, the bit-word length gets progressively shorter, distortion increases and the system loses resolution and becomes "deaf" to some of the subtleties of instrumental timbre and concert-hall ambience. This is the opposite of analog, in which the system gets lower in distortion as the music's level gets lower. Of course, as the analog signal gets very soft, you do hear tape hiss. But the hiss is pretty constant, it does not vary with the music and the ear can hear musical detail even when it's buried deep in the noise. So with analog, as the music gets progressively softer, it sinks slowly but cleanly into the tape hiss, where it can still be heard as music. Not so with digital. With digital, the softest musical details, while not lost in noise, get progressively coarser, then disappear. The deadly digital silence. But there is some noise unique to digital. According to Lawrence Mailander in the summer 1985 issue of The Absolute Sound, the quantization process used in the A/D converter to assign a number to the digital sample produces a noise itself. This quantization noise does not sound like a slight, constant hiss---it changes with the music, adding a smeary quality to the trebles.

Why weren't these problems heard from the start? These exiciting new forms of distortion, brought to us by digital, were unknown with old-fashioned analog---which is why so many people have overlooked them.

It has been said that there are two types of people---failure avoiders and success seekers. There is a world of different between them. These two approaches also affect the way we listen. Many people, when hearing that digital has avoided the familiar noise problems of analog, will conclude that the system is perfect. This is a common perspective of recording-industry workers and equipment sales-people---people whose jobs are made more difficult and embarrassing by production problems such as record pops and ticks. The other type of listener is concerned with certain musical qualities that may be beautifully achieved by high-quality analog, in spite of tape hiss or record pops. Finding those qualities lacking in digital, this listener concludes that analog is superior. Musically sensitive audiophiles tend to listen from this perspective.

Fortunately, there is a growing realization in the industry that digital has a long way to go before it approaches perfection and that high-quality analog has many sonic virtues. At the conclusion of their 1984 Audio Engineering Society paper, Drs. Stockham and Lagadec state, "There are serious reasons for the assumption that digital sound, as it is created today, may be qualitatively different from analog sound and that the difference should be to the disadvantage of digital."

But this realization has come too late for those listeners who prefer the sublime subtleties of high-quality analog sound. If, for example, you want to buy new recordings of the Berlin Philharmonic or the New York Philharmonic but find digital's handling of orchestral string sound offensive (as many do), your are out of luck. These orchestras---and, for that matter, most major symphony orchestras---are now recorded exclusively from digital master tapes, whether the recordings are LPs or CDs. The damage has been done. What if you have heard some of the classic RCA Red Seals of the Chicago Symphony under Fritz Reiner and love their sound? They were recorded in the late Fifties and early Sixties; surely, they must be analog! Sadly, even these are being re-released in both LP and CD---both digitally remastered.

We have a tragedy here. The development of digital audio and the availability of the CD, in and of themselves, are not disasters. For many, this new medium perfectly suits their listening habits and tastes. What is a disaster, however, is the fact that the industry has robbed us of a choice. Indeed, until the serious shortcomings of digital are corrected, a generation of recordings will be lost forever to thousands of musically sensitive listeners.

For those who may applaud the death of the LP---and of analog sound, for that matter---the tragedy may come later. These disciples of digital, seeking perfect sound, forever, have instead found imperfect sound for longer than even they are likely to want it.

But take heart! There is some hope that CDs may not be quite as indestructible as promised. Results of experients by Stan Curtis of Cambridge Audio in England suggest that the CD player's laser beam may damage the delicate pits in the disc's reflective surface. After a few playings, Cambridge's test equipment begins to show progressively increasing error rates. Perhaps it's in the eternal scheme of things that only that which is designed properly in the first place should last forever. It would be ironic injustice, indeed, for survivors of the nuclear winter to have to endure CDs as well as cockroaches.

"The analog approach has evolved to the point where it is capable of astounding accuracy."