Electro-Voice N/DYM 1
Seven-point-two pounds of high-frequency driver that made a company's own industry-standard horn look old overnight.
Overview
The number that matters here is 22.5 kilogauss. That's the flux density Electro-Voice claimed for the N/DYM 1, and the company didn't hedge when it called it the world's highest. The magnet at the center of this driver was a rare-earth supermagnet, and Electro-Voice's own advertising billed it as four times more powerful than the magnets used in conventional dynamic designs. Whether or not that figure survives scrutiny decades later, the intent behind it is clear: this was a driver built to convert more of what it was fed into usable output, and the company's marketing arm was not shy about saying so.
The comparison Electro-Voice kept making was to its own DH1A — a high-frequency driver the company described as the industry standard, the one "some said couldn't be improved." The N/DYM 1 was the answer to that. Electro-Voice claimed a high-frequency efficiency increase of roughly 1.5 dB above 2 kHz over the DH1A, and it delivered that increase from a package less than a quarter the size and at 7.2 pounds — a fraction of the DH1A's weight. That's a genuinely striking pairing of claims: more output, dramatically less bulk. Collectors who have handled both drivers tend to talk about the N/DYM 1 in exactly those terms, as a piece of engineering that made the older driver feel like a different era's solution.
The driver used a dome diaphragm and suspension, and it was built around an MTA-22 adapter offering a standard exit that mates to Electro-Voice's HP-series horns. That adapter detail matters more than it might first appear. The N/DYM 1 was not designed to be used alone — it was one half of a system. Electro-Voice sold it in a configuration paired with a second driver, the two of them feeding a single horn through that adapter. The whole point of the arrangement was to eliminate the comb-filtering interference that occurs when two horns are aimed at the same coverage area. The company claimed the paired system delivered a consistent 3 dB level and power increase at all frequencies across a horn's entire range.
Electro-Voice positioned the N/DYM 1 for situations where size and weight were considerations — the compact, high-output driver for installations and rigs where the DH1A's bulk was a problem. That's a specific and practical brief, and it explains why the driver's physical dimensions got nearly as much attention in the company's copy as its electrical performance. A high-frequency driver that weighs 7.2 pounds and fits in a fraction of the space of the incumbent is a driver you can hang, array, and transport differently.
Recording-Engineer (October 1988, p.29) carried Electro-Voice's claim that the company was first to discover and apply neodymium technology in professional audio products, and the driver's advertising leaned hard on that first-mover status. The claim shows up again in Mix (November 1988, p.42) and in Sound and Communication (January 1989, p.2) — the same campaign, the same boast, repeated across the trade press. Treat it as a marketing position rather than an independently verified fact, but it does tell you how Electro-Voice wanted the N/DYM 1 understood: not as an incremental improvement to an existing driver, but as the opening move in a new material era for compression drivers.
Studio Sound (July 1988, p.34) noted the N/DYM 1's introduction alongside the DeltaMax loudspeaker system, framing both as new Electro-Voice products arriving in the same window. That pairing is useful context. The N/DYM 1 was not a standalone curiosity — it was part of a broader push by the company into new driver technology, and the trade coverage treated it as such.
One detail worth flagging for anyone chasing these today: Electro-Voice's Canadian distribution arm went on record about the shipping timeline. A letter published in Canadian Musician (the general manager of Mark IV Audio Canada writing in response to a December 1989 equipment article) stated that the N/DYM 1 driver had been shipping in Canada since April 28, 1988, and described it as the first production unit of its type shipped anywhere in the world. That's a manufacturer-side claim, not an independent one, but it's specific enough to be useful — and it lines up with the 1988 trade-press appearances.
The driver's identity as a component rather than a finished product shapes how it turns up on the secondary market. This is not a microphone, despite the N/DYM name later becoming strongly associated with Electro-Voice's N/DYM microphone line — a point worth stating plainly, because the naming overlap trips people up. The N/DYM 1 discussed here is a high-frequency compression driver for horn-loaded systems, sold with an adapter and intended for pairing. Buyers looking for the N/DYM vocal microphones are looking at a different product family that borrowed the same technology branding.
For collectors and repair-minded owners, the N/DYM 1's appeal is partly historical and partly practical. The historical case rests on the neodymium-first claim and the driver's role in displacing the DH1A in size- and weight-sensitive applications. The practical case rests on the dome diaphragm and suspension design and the standard-exit adapter, which means the driver can be mated to the horn hardware it was built for rather than requiring a proprietary interface. Documentation for the driver circulates in the form of period trade advertising and the manufacturer's own engineering data sheets, which Electro-Voice invited readers to request by phone — a reminder that the authoritative spec material for this driver was, and to some extent remains, a paper artifact.
What the N/DYM 1 does not offer is a large body of independent measurement. The period coverage is dominated by Electro-Voice's own claims, repeated across several publications, rather than by third-party bench tests. The efficiency increase over the DH1A, the 22.5 kilogauss figure, the 3 dB paired-system gain — these are the company's numbers. They're specific, they're consistent across the campaign, and they're the best available account of what the driver was designed to do. They are not, however, the same thing as a magazine's own measurements, and anyone citing them should attribute them to Electro-Voice rather than presenting them as established fact.
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