The Defiant Audiophile Wades Into The Fray
Of course, the debate rages on over analog vs. digital, vinyl vs. CD, and whether astronomical bit depths and bandwidths really make any difference at your ears. It has been suggested that I don’t appreciate the superiority of vinyl due to my advanced age and the resultant hearing loss that accompanied my often-noisy automotive shop career environment.
Conversely, I argue that it’s not so much a matter of what I DON’T hear, as it is a matter of what I DO hear. It’s not what’s purportedly missing in digital recordings, but rather, what’s variously present in analog ones.
Vinyl records are disadvantaged by many factors, none of which plague the digital process. With today’s vinyl resurgence, some of these factors are minimized but generally still present.
For instance, when the record is pressed, microscopic bubbles in the vinyl biscuit can find their way into a grove and create a “pop” at the most inopportune time. Usually in an otherwise quiet passage, the needle skipping over the microscopic “pot-hole” instantly shatters the illusion of “being there.”
Recently, I tried to digitize an older album from my collection that turned out to have the center hole not quite so “center.” Aside from record warp that creates its own plethora of problems for the stylus cantilever, an off-center hole creates a change in velocity of the groove with every revolution as the diamond tip traces the, now, elliptical path. This results in some long-held notes produced by instruments that are by their nature unwavering in their output frequency to “wow” ever so slightly as they are played. For instance, a Hammond organ note, is by nature a pure frequency, as the perfectly shaped tone wheel teeth pass the pickup coil generator at an absolutely constant speed. A held Hammond note is as steady as they come, but when played on a record with an off-center spindle hole, wavers disconcertingly a few Hz above and below the fundamental with every rotation of the platter adding just a little more “blues” to the Moody Blues.
Dust and dirt in the grooves can be written off as “pilot error” as it should be preventable with proper cleaning and storage, so not the actual fault of the vinyl. But in real-world situations, some surface contamination is almost unavoidable and increases surface noise with each playing. Some of my records have been moved across country from house to house and removed and replaced in their jackets and sleeves countless times over 50 years as they are played for listening enjoyment, which is, ostensibly what they are supposed to be for. Yet, I have seen CD’s inadvertently used as Frisbees and carried in a dog’s mouth that can still play perfectly after being “de-slobbered” in the sink. No multi-thousand-dollar record cleaning machines, no specialized de-ionized cleaning fluid, just some Windex and a rag and the bits are back.
Next, as the stylus traces the groove, no matter how lightly the cartridge tracking force can be set, SOME groove wear is inevitable. Exacerbated by the stylus wear, another inevitable consequence of frictional interaction between two surfaces, each time a brand-new record is played by anything but a brand-new stylus the deterioration process continues. Some engineers postulate that because of the immense instantaneous forces (up to 350 psi) generated by the grove wall as it tries to counter the inertia of the stylus mechanism trying to follow the oscillating undulations of surface, a sufficient amount of heat is generated at the microscopic point of contact to actually soften or even melt the vinyl. Although it cools virtually instantaneously as it leaves the tip, there is none-the-less, no guarantee that the groove wall will regain its exact former contours, potentially altering the sound on the next playing. So far, no evidence has ever been collected that a laser beam modifies, in any way, the bits on the surface of a CD no matter how many times it is played.
And then lastly, for this discussion, is the entire matter of the playback device itself. As mechanical devices, turntables suffer a plethora of potential defects in design or function, all of which can negatively affect the reproduction of the original recording.
Wow, flutter, and rumble, all brought on by inconsistencies in the mechanical challenge of supporting a heavy turntable platter with perfect rigidity in two planes and spinning it at an absolutely constant speed can be, and have been, overcome by the application of increasingly higher numbers of dollars spent on design and construction. Platter bearing rumble eliminated by magnetic levitation, NASA grade ceramic bearings, or oil suspension, speed variances defeated by unbelievably massive platters driven by numerous sophisticated synchronized motors pulling carefully precision ground rubber belts around microscopically accurately machined capstans. All of this can trend to absurdity, as turntables can cost tens of thousands of dollars.
Additionally, the tone arm and cartridge, considered a separate system and function by most audiophiles, and divorced from the job of spinning the record, is another incredibly fragile and technically challenging subsystem.
Traditionally, most audiophiles believe that the optimum contact between the grooves and the stylus tip is one that mimics or matches the geometry of the original cutter head that produced the lacquer master (and, yes, I understand that that is a gross oversimplification.)
But, since the tone arm can be adjusted vertically, the cartridge shifted six ways in the head shell, and the pivot point of the tone arm moved relative to the record platter spindle, dozens of variables can creep into the equation.
It is theoretically impossible to have a pivoted tone arm maintain a perfect tangential relationship to the groove all along the arc that it traces as it traverses the width of the platter. Actually, there can only be two points at which the stylus is perfectly tangent to the groove, and this is largely determined by something called overhang. But, turntable setup experts cannot agree exactly where those two “null” points should be, and hence there are three popular relationships, known as Baerwald, Stevenson and Loefgren alignment. Each has its proponents and its detractors, and disciples of one method often eschew the others. Of course, numerous expensive tools, gauges, and protractors are available to help achieve these settings.
Next, Vertical Tracking Angle adjustment is an attempt to duplicate the angle at which the cutter head originally machined the groove in the lacquer master, theoretically making reproduction a perfect mechanical duplicate of the mastering process. But, record mastering lathe engineers cannot agree on what constitutes the perfect cutting angle and hence it can vary from lathe to lathe and company to company. How then, are we to “duplicate” the angle that was used to create the groove when we have no idea what that original angle was? Tone arms, equipped with micrometer adjustments of VTA can, never-the-less, just be an optimized guess instead of an exact science despite their ability to adjust VTA to within a fraction of a degree. Yet, devotees will insist that even slightly inaccurate VTA has an audible and noticeable effect on playback fidelity.
A lesser known variable knows as azimuth is said to have an even greater influence on playback than VTA, and yet no simple method for verifying or adjusting it is available. Affecting both channel separation and possibly groove wear, azimuth is the left to right tilt of the stylus in the groove, and just making the sides of the cartridge perfectly perpendicular to the record surface isn’t a guarantee, as “experts” maintain that the stylus is often not mounted parallel to the sides of the cartridge. The tool recognized as the epitome of azimuth alignment accuracy is the entertainingly named Fosgate Fozgometer, available on Amazon for only $299.99, but with FREE shipping!
By now, I’m sure you don’t want to hear much more, although we haven’t mentioned anti-skate or the all-important tracking force, which are somewhat related to each other and also of utmost importance to assure proper playback and minimize record wear.
The above discussion only scratches the surface (pun intended) of the raging debate over “proper” vinyl reproduction and, in my view, compares unfavorably to the case for using optical digital media (CD or DVD audio) or, with the advent of relatively cheap bandwidth and storage density, digital download or streaming.
Let me take just a few of the salient points regarding vinyl reproduction and compare them to the process of extracting the music from a CD.
First, let us compare the process of spinning the platter. In playing a record, every factor that is absolutely critical for proper reproduction becomes relatively unimportant when playing a CD. Since the audio is encoded as billions of optically reflective bits and is purely digital instead of analog, things like platter speed, perfect centering, and surface contamination become quite unimportant.
As the digital bits are read from the disk, they are accumulated in a buffer, which then releases them as a perfectly timed synchronized stream to the Digital to Analog Converter (DAC). So, if the platter speed is somewhat inconsistent, the music is unaffected as the only “consequence” is that the amount data in the buffer might vary while it is waiting to flow out to the DAC. This is similar to an old-fashioned well pump that fills a barrel in uneven pumps of the handle, yet delivers a steady stream from a hose at the bottom.
Similarly, if the CD is spinning slightly off center, the flow of bits is unvarying, as all modern laser read heads use a three-beam technology or variation thereof. The center beam stays perfectly aligned with the bit path as the two outside beams scan the “shoulders” of the track and deliver a lower output facsimile of the center beam’s output. If the track moves out of alignment with the center beam, one of the side signals increases in strength as the other simultaneously decreases. This notifies the head motor to correct the position of the reading head to re-center the laser. This happens so quickly, that even at 500rpm, the laser can follow an off-center bit path with little difficulty and still read the bits accurately.
Similarly, even if the disk is somehow “warped” which can make a vinyl record unplayable as the stylus pressure on the grove will vary widely as the inertia of the tonearm and cartridge oppose the ability of the stylus to follow the vertical undulations, a fast reacting lens can vary the focus of the laser onto the surface of an uneven disk to keep it pinpointed sufficiently on the 600 nano-meter wide track.
Since the digital bits are read by a beam of carefully focused laser light with no physical contact, playback wear is impossible to create. But, since scratches and dirt can obscure some of the bits a method to correct for the missing bits has been developed using data redundancy and predictive mathematics. A microscopic speck of dust can disturb the accurate tracing of a record groove wall and create a disturbing audible artifact during playback and may even result in the embedding of the dirt speck in the heat-softened vinyl by the pressure of the stylus on the groove wall, forever repeating the “click” at that spot. If some of the digital bits are obscured by surface contamination of a CD, there are logic circuits built into the player that can reconstruct the missing bits based on the pattern that precedes and follows them. Since the bits undergo significant buffering and processing before being sent to the DAC for eventual conversion to an analog sound stream, there is plenty of time for them to be analyzed in the digital domain and repaired and reconstructed as necessary before being converted.
Of course, we have all had a CD “skip” indicating that so much data were missing that there was not enough information left for the player to predict the values of the missing bits, but in any event, the sonic consequences are not nearly as severe as when even one tiny portion of a record groove wall is damaged. Lastly, the fragile grooved vinyl surface of an LP attracts and traps foreign material which, once settled or pressed down into the groove is nearly impossible to remove, whereas the smooth hard surface of a polycarbonate CD can be squirted with Windex and polished off with an old T-shirt dozens of times without damaging the data within.
Now consider the effect of the cartridge in the playback process. Just as one would expect a microphone to impart its own signature on the sound that is ultimately recorded, so does a phono cartridge. But, the choice of microphones is usually a carefully considered one made between the performer and the recording engineer as to capture the artist’s conception of what he / she wants their signature sound to be.
Many performers insist on touring with their own microphones and using them even in the studio because of the way that particular microphone suits their vision of what they should sound like. Differences in microphone construction and the different mechanical technologies used to convert the vibrations in the air to an analog electrical signal give every microphone its own unique sound signature. Vocalists gravitate to one brand and model and instrumentalists to another. No band would use the same microphone to pick up the kick drum as they would to record the lead singer.
Conversely, precisely because a phono cartridge does virtually the same job as a microphone except that it picks its vibrations from the groove wall rather than the air, it must exhibit the same variances in design, construction, and output as do microphones. Hence, cartridges also have a “signature” sound and cannot help but color the playback of the recorded signal.
But, whereas the performer has agreed to a particular coloration imparted by the microphone, often through many years of trial and error and recording and listening until their sound is perfected to their satisfaction, using a phono cartridge that alters the sound, however slightly, during playback deviates from what they recorded and from what they wanted to sound like.
Since digital recording isn’t subject to coloration from the laser, one will ultimately get back out of a CD track the exact sound that the performer and engineer laid down on it.
Of course other components in the chain of reproduction can, and do, each add another potential layer of coloration to the signal, and there is no argument to the fact that the single largest contributor to that coloration is due to the choice of loudspeaker and its room interactions. But, eliminating the phono cartridge removes fully one-third of the possibility of distancing the output from the recorded sound, as the three major contributors to coloration are always going to be the devices within which mechanical motion is converted to electrical signal or vice versa; that is the microphone which adds coloration “approved” by the performer, and the phono cartridge and speakers each of which can widen the separation between the performer’s intent and the listener.
So, with every aspect of the mechanical operation of a turntable so critical and so fussy and sensitive to microscopic variances in speed, position, angle, and force and with the necessary practice of reducing the amplitude of recording head excursions at low frequencies to prevent excessive acceleration of the stylus cantilever on playback (and to lengthen the potential recording time on a given record side by artificially “narrowing” the record groove, called RIAA Equalization), it is a near miracle that the process works at all.
Conversely, the mechanical and optical system that spins the CD, tracks the “groove,” and picks up the recorded signal is so forgiving and so non-critical that an inexpensive portable CD player can be constructed and sold at retail for less than the price of even the cheapest phono cartridge replacement stylus, and at that price can even offer anti-skip prevention by the inclusion of a larger buffer and a logic circuit that has the ability and time to re-read suspect bit streams and correctly splice them into the skipped portion before playback.
Lastly in this comparison of technologies, two more important factors come into play. First, in most phono cartridges the “arm” (cantilever) that supports the microscopically small stylus tip must convey the undulations of the record groove to the electrical generator mechanism in the cartridge body, whether that generator be moving magnet or moving coil (or in rare cases, moving iron). To accurately accomplish this critical function, it must be intrinsically very rigid and inflexible, lest it allow or induce harmonic vibrations at some frequency, but it must be flexibly supported as it enters the cartridge shell to allow movement at the stylus end to be transmitted to the magnet end where it excites the cartridge coils (MM cartridge example). Thus, the rigid cantilever passes through some sort of flexible suspension support (grommet) on its way into the cartridge body.
This critical piece of flexible material can be made of a variety of materials, with some manufacturers using butyl rubber, nitrile, or a silicone rubber, but a material that, in any case, can and does change its compliance, torsilastic resilience, and flexibility over time. If this tiny bit of material softens over time, the weight of the cartridge will deflect the suspension farther for a given Vertical Tracking Force (VTF) and in severe cases allow the cartridge body to ride so close to the record surface that it may actually strike the rotating platter surface unless it is perfectly flat. This “collapsed suspension” is easily fixed by replacing the stylus assembly, but even for many consumer level cartridges, can be somewhat expensive.
Conversely, the suspension grommet can harden with time severely skewing the compliance and frequency response of the cartridge, and again, requiring replacement of the “needle” (a lovely throwback reference to the days of 78 RPM records which were played with an actual sharpened rod of metal clamped to a semi-flexible disk of metal at the small end of an increasing diameter horn).
In either case, this means that even an un-played cartridge at no risk for stylus wear can fail unpredictably over time and become useless. One subject expert claims that this suspension deterioration affects the output in an audible way in as little as two years time “whether you are playing records or not.”
Second, it is the function of the cartridge to generate an electrical signal, typically measured in a fraction of a millivolt (in a moving coil (MC) design) which then must be amplified by an order of thousands of times before it can drive a speaker coil. It accomplishes this output with deflections of the stylus that are measured in millionths of a millimeter as it traces the record groove wall. It is simply inconceivable in a typical listening room environment that the audiophile can isolate and insulate the turntable structure so perfectly that neither the tonearm / headshell / cartridge combination nor the entire turntable and its support structure will never be influenced to move just a millionth of a millimeter in relation to each other as the record is playing. This is especially unrealistic where the speakers and the turntable share the same room and the very act of vibrating the air to produce the desired sound output cannot help but impinge on the surfaces of the turntable. Known as feedback, these induced motions create a type of distortion as an echo in the output that deteriorates the quality of the output. In any urban environment, the constant stream of vehicle traffic perceptibly vibrates the ground under virtually all the structures for hundreds of yards in every direction. A millionth of a millimeter is a very tiny deflection indeed and heroic steps are taken to try and prevent feedback in turntable systems. But, can it be completely eliminated in all but the most complex installations? Not! Yet, you can take a $20 portable CD player jogging and never skip a beat.
In conclusion, please remember that you are reading my opinion, with which you are totally free to disagree, take issue, and even dispute passionately. I maintain that our devotion to vinyl records as a music reproduction medium stems more from historical passion than mechanical logic. Of course, there are thousands of vinyl records that capture performances that would otherwise be lost to society forever. In a desire to experience this vast collection, it makes perfect sense to employ the only available playback technology epitomized to as fine a level as budgets and tastes allow. It is within the scope of my very own arguments that, given a particular record, it will always sound better on a carefully designed constructed and installed audiophile turntable system than on a $49.99 Crosley Suitcase record player.
Toward that end, a Japanese company, ELP, designed and marketed a “turntable” that reads the record groove with a pair of laser beams, completely eliminating contact wear and a huge percentage of the surface noise. It also eliminates $15,000 from your bank account, which in light of the more conventional mechanical Goldmund Reference II at $300K, is a bargain.
But, as a music storage and retrieval system for “current” and available performances, technology has indeed “moved on” and capturing, storing and subsequently re-playing music is far better accomplished fully in the digital domain until the very last millisecond before it emerges from the speakers.