He AR-1 is a three-way loudspeaker with a 15 woofer driven by a 500W, Sunfire-designed amplifier. Its tower-style enclosure is constructed from ¾ particleboard with picture-frame internal bracing. The tweeter is a 1, plasma-transferred, diamond-coated titanium dome. Surrounding the tweeter is an “energy-control contoured baffle, ” an integral waveguide for the tweeter made of foam of varying density, which controls the unit’s dispersion. This foam ring was used, said Mike Park, to produce a smoother off-axis response pattern by eliminating the edge-cancellation effects of the speaker’s narrow front baffle. Above and below the tweeter are a pair of 5.25 midrange drivers in a D’Appolito configuration. Each of these has a monocoque concave cone-with no dust cap-made from a very stiff magnesium-aluminum alloy. A 1 copper voice-coil is wound on an aluminum former, this said to double the sound-propagation velocity through the cone material and to lower the second and third harmonic distortion compared to a paper midrange cone. Each midrange driver is housed in a specially formulated, compressed-pulp sub-enclosure to provide isolation from the woofer. The 15 is mounted near the floor, on the cabinet’s side-the speaker is supplied as asymmetrical pairs, with left- and right-hand versions. Like the other drivers, the woofer is magnetically shielded. It is driven by an internal, high-efficiency amplifier designed by Sunfire Corporation and licensed to AR that uses a tracking down-converter (TDC). This amplifier features continuously variable power-supply voltages slightly higher than and in sync with the audio signal. Sunfire claims that the design allows its TDC amplifier to approach 85% power-conversion efficiency compared to the 20-30% of conventional designs. This amplifier can thus be a small, lightweight, cool-running, low-cost unit. Its built-in limiter IPC (intelligent parameter control) circuit provides an excursion limiter, a dynamic compressor, a thermal rollback limiter, active low-frequency equalization, infrasonic filtering, and automatic, signal-sensing amplifier turn on/off. The woofer is solidly, ruggedly constructed. It employs a 4-lb magnet, a vented pole-piece to improve voice-coil cooling, a half-roll foam surround, a and a two-layer, long-throw, copper voice-coil, 4 in diameter and wound on an aluminum former to provide high heat dissipation. Its rib-reinforced cone is made from a formulated paper material chemically treated with a clear polymer “Hydra-Plas” resonance-damping compound to reduce distortion and cone breakup. To further increase cone stiffness, the dustcap is inverted. The latest AR-1 includes equalization circuitry to allow the bass-level control to act as a narrow-Q parametric equalizer around 30Hz.