Tannoy CPA-5
A five-inch dual concentric that won't blow its tweeter - the tweeter has no coil to burn.
Overview
The CPA-5 is the smallest member of Tannoy's Contractor Series, a line of sound-reinforcement loudspeakers built for installers rather than audiophiles. The big design choice is the driver: a 5-inch dual concentric based on Tannoy's Inductive Coupling Technology, or ICT. The high-frequency section is a 1-inch Duralumin dome driven inductively instead of by a conventional voice coil. No coil, no windings, and so, as the period literature liked to point out, no way to blow it up. Tannoy's own advertising in Mix-Magazine (May 1992, p.23) leaned hard on that pitch. It paired the "impossible to burn out" HF section with a claimed 100 watts of power handling and 110 dB of output from a cabinet measuring just 8½ by 6 by 5 inches.
The HF dome sits at the acoustic center of the woofer, and there is no crossover network between them. That makes the CPA-5 a point-source, crossover-free design, and time delays and phase anomalies are eliminated by design rather than by correction. The tradeoff is built in. A single 5-inch cone asked to cover everything below the dome will not deliver deep bass, and Tannoy knew it. The company's answer was the CPA 5 SB, a passive bandpass subwoofer built to sit under small, high-powered monitors like the CPA-5 ITC. According to Recording-Engineer (August 1992, p.53), that companion box packed four 5-inch low-frequency drivers into a jet-black enclosure measuring 21.6 by 11.8 by 7.8 inches, weighed 31 pounds, and carried a retail price of $495. Its rated response ran from 46Hz to 210Hz. That is a narrow band, on purpose, because it was never meant to reproduce anything above the crossover to the satellites.
The sub's electrical behavior explains how the system is meant to be wired. Stand-alone, the CPA 5 SB presents a 12-ohm load. Coupled to mid/high satellite speakers, the working load drops to 6 ohms. Sensitivity is rated at 93dB SPL at 1 watt at 1 meter, and power handling at 150W. Tannoy claimed the bandpass alignment generated sound levels in excess of 4dB higher than conventional subwoofers driven by the same amplifier. That is an efficiency argument, not a depth argument.
The compact footprint was aimed at keyboard players and MIDI workstation operators, per the period product announcements, and at limited-space environments generally: control rooms, edit suites, and contractor jobs where a full-size monitor would not fit. The Mix-Magazine (September 1991, p.120) new-product column introduced the broader CPA Contractor Public Address Series as gear "designed for the sound reinforcement" market. This is a working loudspeaker, not a hi-fi artifact.
It is a point-source problem-solver for tight spaces. Collectors after the Tannoy dual-concentric sound on a small scale will find the ICT driver interesting, since the inductive HF coupling is an engineering curiosity and the crossover-free topology is rare in any era. Anyone expecting the scale and weight of Tannoy's larger concentric monitors will be disappointed. The CPA 5 SB is effectively mandatory if bass below roughly 200Hz matters to the application.
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