MACH 1 Acoustics? Cute name. Mach 1 is, of course, the speed of sound—the speed at which a loudspeaker's acoustic output is forever constrained to travel. Quite a fitting choice for Marc McCalmont, Marine and jet pilot turned speaker designer. Marc retired to Wilton, NH together with Melissa. (Oops, that should be MLSSA, the well-known acoustic analysis system—not Marc's girlfriend.)
The Model R107 represents the flagship of KEF's Reference Series, and is second only to the Professional Series KM-1 in KEF's product line. Anatomically, the 107 resembles a person. Beneath a decorative "hat," there's a special head assembly akin to the head on the old Model R105. This head assembly contains the brains of the 107, namely a T33 ferrofluid-cooled tweeter and an improved version of the classic B110 midrange driver, featuring a better voice-coil and a new polypropylene cone. The nerve center is also here, in the form of two passive dividing networks and load-impedance equalizing network. Level equalization of the drivers is performed actively within the KUBE, the second brain of the 107—about which you'll hear more shortly.
Let me take you back some 40 years to the mono days of the early 1950s. It's unlikely that the minimonitor genus of loudspeakers, of which this French JMlab is a prime example, would have survived back then. There was the practical problem of available amplifier power. The average amp could squeeze out no more than 10 to 15W into an 8 ohm load—far less power than the typically insensitive minimonitor demands for adequate dynamic headroom. But that in itself would not have sufficed to displace the minimonitor from the marketplace. After all, "high-power" amps (50-watters) could be had at a price.
It was back in the mid-'70s that David Berning made a name for himself in the Baltimore-Washington area as an avant-garde designer—someone with a truckload of fresh ideas about tubes. At the time, though Audio Research was starting to crank out pretty decent amplifiers, tube design was pretty much reduced to a rehash of the Williamson circuit and the Dynaco mod of the month.
As Laura Atkinson shuffled into my listening room one evening, she spied the Stage loudspeakers tucked away in the corner. "Hey, Dick, those look like Apogees, but they're kind of small." Rising to the occasion, I responded with: "Honey, I shrunk the Apogees." At roughly 3' tall by 2' wide, the Stage is far from intimidating; it even feels more compact and is certainly much cuter looking than the old Quad ESL. Yet Junior's resemblance to the rest of the Apogee family is unmistakable. The canted baffle, the vertical tweeter/midrange along the inside edge of the baffle, and the pleated aluminum-foil woofer clearly bear the imprint of the larger Caliper and Duetta models. It's almost as though Apogee started shrinking the Duetta until the price tag shrank below two kilobucks.
A.C. Wente of Bell Telephone Labs was apparently the first person to get the bright idea (in the 1930s) of measuring sound transmission in a small room. A loudspeaker at one point reproducing pure tones of constant power, and a microphone at another point measuring sound-pressure levels, gave him the means to assess the room's impact on sound quality. The measured frequency response was so ragged that I'm positive the venturesome Dr. Wente was duly shocked.
Frankly, I'm fed up with the prophets of doom, those false seers who forecast vinyl's imminent demise. Some claim to have seen the writing on the wall as far back as ten years ago, sensing that the advent of the CD would perforce relegate the stylus-in-groove method of transduction to the trashpile of history. First of all, most of the music I enjoy happens to be on LP. And I'm sure I speak for many audiophiles who have also spent a lifetime building up a vinyl collection when I say we're not about to throw away our cherished treasuries of music. These LPs I expect to enjoy until the end of my time. Thus, I welcome any phono-system technological advance that will recover more information from the groove.
Lee de Forest filed for a US patent on his "Audion"—the first triode—on October 25, 1906, but never could explain why it worked (footnote 1). It was up to Armstrong and Langmuir, in their pioneering work, to place the hard-vacuum triode on firm scientific ground. When the US entered World War I in April 1917, the Army had to rely on French tubes. Six months later, Western Electric was mass-producing the VT-1 receiving tube and the VT-2 transmitting tube. However, it was only in the decade following World War I, as designers became conversant with the triode amplifier, that many of the crucial elements of tube amplification were nailed down. Technical issues such as coupling two gain stages and selection of optimal coupling impedance were already resolved by the mid-1920s. The triode ruled supreme until the tetrode came along in 1926, followed in 1929 by the pentode from Philips's research laboratories in Holland.