I have flip-flopped between these points of view: that some audio products or technologies are better suited than others to specific styles of music, and that any good product or technology should be equally at home with rock’n’roll, chamber music, large-scale classical, hard bop, techno, ragas—even George Crumb.
At age 19, in my first job as a hi-fi salesman, I was asked to adopt the first of those views. The shop I worked in carried only two loudspeaker lines—EPI and Ultralinear, both long gone—and the owner urged me to push the former on lovers of classical music, and the latter on rock fans (footnote 1). So I did. To paraphrase Jiang Qing, I was the shopkeeper’s dog: What he said to bite, I bit.
At various times in my life as an audiophile, I have tried to adopt the other, more absolutist point of view—sometimes for good reason, sometimes just for the fun of it, never with lasting success: I persist in thinking that, when choosing playback gear, it’s best to bear in mind one’s favorite records. And now I’ve discovered that a setup technology I’ve used for decades itself depends on the music I play, if obliquely. (There’s a joke in there. Sort of.)
Angling for complements
By now, most serious phonophiles recognize the need to properly align a phono cartridge relative to both the tonearm that holds it and the center of the turntable’s platter, to minimize lateral tracking error. LTE is created by discrepancies between the radial line traveled by the cutting stylus when an LP’s master is created, and the arc traveled by the playback stylus of a cartridge mounted in a pivoting tonearm—discrepancies that result in measurable and audible distortion.
In the 1920s, it was suggested—by an audio journalist! (footnote 2)—that a pivoting arm’s LTE could be minimized by modifying the cartridge’s position in two ways: angle its body laterally so that the cantilever and stylus point inward toward the record spindle by a precise angle called the offset, and position the cartridge so that the arc traced by the stylus has a radius longer than the distance between the spindle and the tonearm’s pivot. The latter ensures that the stylus of a cartridge so mounted extends beyond the center of the spindle by a similarly precise distance called the overhang.
In 1938, that suggestion was refined by an engineer named Erik Löfgren (1896–1987). He modeled the problem as one in which playback alignment is defined by a series of triangles on a lateral plane, each comprising one moving point (the position of the playback stylus) and two fixed points (the center of the record and the point around which the tonearm pivots). From that, he devised a series of geometric calculations, weighted to take into account the record’s dimensions (I’ll come back to that in a moment) and the preemphasis/deemphasis curves used in its making. The result was an alignment scheme in which the playback stylus exhibits perfect tangency—and thus zero LTE—at two null points along the tonearm/cartridge’s arc of travel, and minimal LTE everywhere else along that arc.
It caught on: 80 years later, we’re still using Löfgren’s alignment, or variations thereupon (footnote 3).
The story doesn’t end there. As hinted above, phono-cartridge alignment is also governed by the points at which the modulated portion of the groove begins and ends. The beginning point, typically 146mm from the center of the spindle, isn’t crucial, but the ending point surely is: as groove radius decreases, distortion goes way up. The apparently popular explanation—that a tightly curved groove impedes tracking by means of a “pinch effect”—has merit but is incomplete; arguably more critical is the fact that, despite the disc’s unchanging speed of rotation, the linear velocity at which the groove is dragged under the stylus is considerably slower at the end of the groove than at the beginning. As the record-mastering lathe nears the end of the groove, it crams a consistently complex signal into an increasingly small expanse of vinyl, setting the stage for a progressive rise in distortion upon playback.
Recognizing this, Löfgren put the innermost of his two null points at the innermost modulated groove of the record, about 60mm from the center of the spindle (but see below!). To some observers, that’s small comfort: with Löfgren’s alignment, the increases in distortion before and after the outermost null are abrupt, and the rise in distortion as the stylus travels from the innermost null point toward the spindle is even steeper: for the stylus to continue even a few millimeters beyond that inner groove is to see a drastic jump in LTE-related distortion. And as Keith Howard brought to light in his article “Arc Angles: Optimizing Tonearm Geometry,” in the March 2010 issue of Stereophile, records with modulated grooves nearer to the spindle than 60mm are not uncommon.
And here we arrive at the program-specific part of this scenario: In the world of classical recordings, the need to fit an entire three- or four-movement work on a single LP is obvious. Except when it’s unavoidable (eg, the first movement of Mahler’s Symphony 3), record producers are loath to begin a movement on one side of an LP and continue it on another.) And in the standard repertoire there’s no shortage of symphonies and concerti, not to mention individual movements within those works, that end with a climax, often played fortissimo. Thus the most complex, high-amplitude passages wind up being pressed into the parts of the groove that are the hardest to trace.
And here we arrive at a discrepancy that’s been hiding in plain sight all along: In 1938, when Erik Löfgren published his work, there were no such things as LPs.
Enter the Smartractor
In 1938, there were only monophonic shellac discs that spun at a high-resolution–friendly 78rpm, and whose jumbo grooves—more than twice as wide as an LP’s microgroove—were, in some instances, modulated to within a few millimeters of the paper label. Before the microgroove LP, which Columbia Records introduced in 1948, classical record producers had no choice but to stretch a single movement across multiple sides or even multiple discs; in fact, before 1947, during the era when all commercial recordings were made direct-to-disc, producers and engineers got pretty good at it. (The art of acoustic orchestral fade-ins and fade-outs is now surely lost to us.)
The discrepancy of using a 78rpm-era phono-alignment scheme to optimize the sound of 331/3rpm stereophonic microgroove LPs did not go unnoticed by Dietrich Brakemeier, of the German firm Acoustical Systems (footnote 4). Beginning in 2010, Brakemeier set about creating a new alignment scheme tailored specifically to stereo microgroove LPs. The result of his work is a curve he calls UNI-DIN, the first three letters of the name being derived from universal, the last three standing for Deutsches Institut für Normung (German Institute for Standardization), one of the organizations that establishes, among other things, the standard characteristics of commercial LPs.
As Brakemeier suggests on the Acoustical Systems website, he developed his alignment scheme with some specific goals in mind, not the least being even lower distortion from an LP’s innermost groove—for which the UNI-DIN curve trades “slightly higher [deviation] at the beginning of the groove—where the overall working conditions for the stylus are the best.” Arguably more important was Brakemeier’s goal of creating a curve in which increases in distortion are less drastic than in any other alignment—something he says is critical because “the human ear . . . is very sensitive to changes.” Brakemeier suggests that the UNI-DIN distortion curve is “actually flatter than the other curves, in the sense that the inevitable dips and peaks of [deviation] in the tangential curve are smoother—less steep/fast in both directions.”
To achieve these goals, Brakemeier used a design approach that, while it does involve two null points, differs from those employed by H.G. Baerwald, J.K. Stevenson, B.B. Bauer, J.D. Seagrave, M.D. Kessler, and B.V. Pisha—all of whom have proposed alternative phono-alignment schemes—in not being based on Löfgren’s alignment. “I did not base UNI-DIN on Euclidean calculations,” he told me via e-mail. “[It] was first planned, then designed, and then calculated.” Brakemeier has not published his data, and regards his alignment scheme as both his intellectual property and the commercial property of Acoustical Systems, of which he is the chief design engineer. That choice has led to at least one clash: Not long ago, against Brakemeier’s wishes, a competitor published a graph purported to compare the distortion curves of various alignments, including UNI-DIN. But the graph was based on an incorrect guess at UNI-DIN’s underlying calculations, and thus misrepresented Brakemeier’s curve—to the advantage of the competitor’s preferred alignment, of course.
Footnote 1: Not that anyone ever heard rock in that shop. It had been banned by the owner, a born-again Christian who ordered me and the store’s other employees to put religious tracts—crazy little wads of fevered bigotry that equated long hair on males with homosexual tendencies and the “devil’s beat” in black music with drug abuse and violent crime—in with every piece of merchandise that left the store. I can laugh about it now.
Footnote 2: That would be Percy Wilson (1893–1977), professional engineer, amateur spiritualist, and Gramophone magazine’s original technical editor, who also conceived of the first wet-wash, vacuum-dry record-cleaning machine.
Footnote 3: In 1941, Erik Löfgren’s work was translated from German into English by H.G. Baerwald, whose name was thereafter associated with what we now refer to as either Löfgren A or Baerwald alignment.
Footnote 4: See my review of the Acoustical Systems Arché headshell in my May 2018 column.
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