Electro-Voice EVM-12L
A 12-inch driver that pros loaded into horn cabinets by the pair, and that still turns up in bass rigs.
Overview
The EVM-12L is the extended-range member of Electro-Voice's EVM Pro-Line, a driver family the company rolled out to replace its Series II units with significantly more power handling. The numbers: 300 watts continuous, with program peaks up to 1,200 watts under EIA Standard RS-426A test conditions. That's double the power-handling capacity of the drivers it replaced, and DB Magazine (July 1983, p.49) noted exactly that when the Pro-Line series was announced. The new drivers doubled the capacity of the outgoing EVM line. For anyone running a working PA in the early '80s, that meant fewer recones, fewer blown drivers mid-set, and a 12-inch box you could push hard without babysitting it.
The 12L differs from its near-twin, the EVM-12S, in voicing. The two are almost identical in construction, but the -12S is tuned for extra emphasis in the 2 to 3 kHz range, which adds brilliance and punch for full-range use. The -12L is intended for extended-range sound reinforcement. In practice that means it trades a bit of that upper-mid aggression for a more even, extended top end. It's the one you'd pick when the box needs to cover more ground than just kick and snare.
The engineering behind the Pro-Line family centered on heat. Both the voice coil and the magnetic structure are vented to maximize heat dissipation in the voice coil area. That matters once you're running a driver at 300 watts continuous for hours. The assemblies use EV's largest 16-pound magnetic structure, and the voice coil is low-mass edgewound flat-wire construction with heat-resistant materials throughout. A big motor and a light, efficient coil gave the EVM-12L its reputation for staying clean at levels that would cook lesser drivers.
The Pro-Line speakers were designed to work in both vented (bass reflex) and horn enclosures. EV's engineers developed six optimally-vented enclosures specifically for the new line, with low-frequency limits (3 dB down) spanning 38 to 83 Hz and internal volumes from 1.3 to 13.0 cubic feet. That covers everything from a compact monitor to a serious sub cabinet.
Pro-net pricing at launch put the EVM-12S and EVM-12L at $200 each. That was real money in early-'80s dollars, and these were aimed at working professionals. The 15-inch models ran $220, and the 18-inch EVM-18B topped the line at $330.
In the Field
The EVM-12L's second life came in folded-horn cabinet designs. Bill Fitzmaurice's DR-series horn projects, the DR12 and the smaller DR12a, both specified the EVM-12L as the recommended premium 12-inch driver. In his DR12 writeup, Fitzmaurice cited the driver's superior high end as the main reason for the recommendation. He also noted that its light dust cover acts as a midrange cone, giving superior mids until voice-coil inductance chokes off response.
The DR12a project documentation lists the EVM-12L's nominal specs as Fs 55 Hz, Qts 0.25, Vas 2.5 ft³, and SPL 100 dB. Fitzmaurice's own well-broken-in sample measured an Fs of 48 Hz after years of use. These drivers loosen up considerably with age, so a 20-year-old EVM-12L may not match its factory numbers. For the DR12a cabinet, the recommended driver Fs window was narrow: no lower than 45 Hz and no higher than 60 Hz, with 55 Hz described as the best target. A driver below 45 Hz would cause a response dip, and above 60 Hz would kill the first octave. The EVM-12L, at its specified 55 Hz, sits inside that window.
Measured performance in the DR12 horn was strong: average woofer sensitivity of 109 dB (±4.5) from 100 Hz to 5 kHz. The same driver in a 1.5 ft³ closed box averaged only 100 dB, and showed a peak at 4 kHz that the horn cabinet smoothed out. The horn kept an 8 dB advantage over the closed box right to the limit of the driver's range. That's bandwidth comparable to a direct radiator, which is unusual for a folded horn.
The DR12a documentation is plain about where the EVM-12L doesn't shine. For guitar, the recommendation was blunt: don't. A 1.5 ft³ closed box with an EVM-12L has more than enough stage volume for players who'd rather not go deaf. For keyboard, it would sound great but the cabinet is bigger than necessary unless you're playing stadiums. Bass was the maybe. The DR12 out-powered a commercial four-ten/eighteen sub setup, and with its 5 kHz bandwidth the EVM-12L could work without tweeters, though tweeters were suggested for an airy top end on slap and pop funk bass.
That 5 kHz ceiling matters for how you use it. The EVM-12L is not a full-range driver in the hi-fi sense, and it rolls off well before the top octave. For bass guitar, PA, and keyboard applications where a tweeter handles the air, that is fine. It covers more ground than a dedicated woofer while still delivering serious low-frequency output in the right cabinet.
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