Historical

The quest for a full-range electrostatic loudspeaker has occupied many engineers' minds for many years. The problems are manifold: large physical size (which can lead to room placement problems and poor dispersion), the difficulty of achieving high sound pressure levels, the need for a potentially sound-degrading step-up transformer, and the unsuitability for production-line manufacture. Even so, the potential rewards are so great that one can understand why loudspeaker designers keep on attempting the apparently impossible. Epoch-making models do appear at infrequent intervals, keeping the flame burning since the appearance of the original Quad in 1955: Acoustat, Sound Lab, and Beveridge in the US, Stax in Japan, Audiostatic in Holland, Quad, of course, in England, and now MartinLogan.

"A thing divine—for nothing natural I ever saw so noble."

"Who Stole The Bass?" asked Anthony H. Cordesman, writing about minimonitors in the April/May 1987 Stereophile (Vol.10 No.3). And for the designer of a box loudspeaker, the fundamental design decision, at any price level, is how much bass extension to aim for. It will always be possible to design a speaker with extension down to 20Hz, but will the result be musically and commercially successful? Will the designer end up with a speaker hypertrophied in that one area at the expense of every other? Will, indeed, the result be feasible technically? For example, for a given cabinet volume, gains in low-frequency extension have to be balanced against corresponding drops in sensitivity, and it is quite possible that to go for 20Hz extension will result in a 60dB/W/m sensitivity, equating with a speaker that only plays extremely quietly, and thus of no use to anyone.

This is something we don't see too often: an entirely new approach to power amplifier design. As Quad points out in its literature for the 405, class-A operation of transistors provides the lowest distortion, but drastically limits the amount of power an output transistor can deliver without overheating. (Most transistor amps use class-AB output operation, in which each of a pair of power transistors handles part of each signal cycle and shuts down during the other part. Imperfect synchronism between the two halves causes the familiar "crossover distortion," which accounts for most solid-state sound. In class-A operation, each output transistor draws current though the entirety of each signal cycle, eliminating the crossover transition but doubling the amount of time current is drawn, and thus tending to cause the transistor to heat up more.)

Several issues back, we reviewed rather enthusiastically a pre-production prototype of this preamp. The original was an unprepossessing-looking device on two chassis, interconnected by a 3' umbilical, with a squat little preamp box and an even squatter power supply with humongous cans sticking out the top. We averred that it sounded nice. The production model is so nicely styled and functionally smooth that we wondered if it might not be another Japanese product. 'T'ain't.

From London, England, to Santa Fe, New Mexico, is a pretty big jump, both geographically and culturally. From Hi-Fi News & Record Review to Stereophile, however, is a mere hop; the similarities overwhelm the differences. Unlike the US, mainstream magazines in the UK have managed to keep in touch with the fact that hi-fi components sound different; to edit and to write for an ostensibly "underground" American magazine presented no major philosophical problems. (I say "to edit," but as mentioned in "The Big Announcement," Vol.9 No.3, my editing is done in harness with Stereophile's founder and guiding light, J. Gordon Holt.)

I must confess to a certain sentimental affection for Magnepan products. An early version of the Tympani did more to rekindle my interest in audio than any other speaker I can think of. In a world which seemed doomed to finding out just how small and dull it could make acoustic suspension boxes, the Magnepans reminded me that speakers could produce a large open soundstage, real dynamics, and musical life.