Electro-Voice SP-12B
A twelve-inch coaxial that Electro-Voice kept calling a "best buy" for over a decade - and the period press kept agreeing with.
Overview
Electro-Voice sold the SP-12B as a twelve-inch Radax coaxial, a two-way system built around a single 12-inch frame with a second cone element handling the top end. That means one driver, one mounting hole, and wide polar distribution from the coaxial layout. Electro-Voice's own literature described it as the smoothest and widest-range speaker available in its price class. It paired that claim with an efficiency argument: a high-efficiency design gives full, clean output from a modest amplifier rather than brute power.
The published response figures come in two flavors. Usable response ran 25 to 16,000 cps. Flat response was quoted at ±6 dB from 35 to 13,500 cps, and that flat figure was specified in the recommended Aristocrat folded corner horn enclosure, not free-air or in a sealed box. So the SP-12B was designed to be partnered with a specific cabinet. Electro-Voice published impedance curves taken in the Aristocrat, along with intermodulation distortion plots versus power input, and pointed to low distortion at normal room levels below 5 watts. The pitch was efficiency and low distortion at realistic listening levels, not raw wattage.
The Radax second cone is what gives the SP-12B its dispersion. Electro-Voice's literature made a point of even coverage across the listening area at all frequencies, illustrated with polar curves at three discrete frequencies. The high frequencies radiate from the same axis as the low, so the sweet spot doesn't collapse into a narrow beam the way a separate tweeter can.
Pricing moved. A 1965 HiFI-Stereo listing put the SP-12B coaxial at $37.00 and the three-way 12TRXB at $66.00. By the time of a later dealer listing the SP-12B carried a $41.25 list price. Electro-Voice's advertising leaned hard on value. The copy described the SP12B and 12TRXB as chosen for over a decade as "best buys" by listeners and laboratories alike, and closed by noting the line was very modestly priced. That's marketing copy, not an independent verdict.
The independent reception is thinner than the ad run suggests. The SP-12B shows up repeatedly in period dealer listings and in Electro-Voice's own placements. HiFI-Stereo (September 1965, p.85) carried the "best buys" page with the $37.00 coaxial price, and the same advertisement reappeared in HiFI-Stereo (May 1966, p.120) with identical pricing. What the surviving record mostly documents is a speaker that dealers stocked and bundled rather than one that reviewers measured in isolation.
A twelve-inch coaxial at that price, efficient enough to run off a modest amplifier, suited a first serious hi-fi system, and Electro-Voice built the Aristocrat enclosure and the matching kits around exactly that use. Anyone chasing one today should expect to find it in or alongside an Aristocrat cabinet. Verify the cone and the coaxial element before assuming the published response figures apply, since those numbers were tied to the recommended enclosure.
Electro-Voice ran the "best buys" campaign across years and multiple publications. The speaker's identity as a value coaxial - efficient, wide-dispersing, enclosure-dependent - stays the same throughout. The period independent press largely left the "best buy" question to the buyer's ear.
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