AR 9

About the AR 9

The Acoustic Research AR 9, produced between 1977 and 1982, is a large 4-way, 5-driver floor-standing loudspeaker system featuring two 12-inch acoustic suspension woofers, an 8-inch midbass driver, a 1.5-inch upper midrange dome, and a 0.75-inch dome tweeter. It delivers a frequency response from 18Hz to 30kHz with a low system Q of 0.5 at resonance, providing powerful, clear bass and smooth, articulate highs. The system uses a large 120-liter enclosure to achieve a low resonant frequency and incorporates a sophisticated crossover network with electronic automatic transmission circuitry that maximizes damping at resonance while maintaining flat bass response. The speaker weighs approximately 59 kg and measures 1340 x 381 x 402 mm. It is designed for high power handling up to 400W maximum and has an impedance of 4 ohms with 87 dB sensitivity. The cabinet is finished in American walnut veneer, and the design includes acoustic blankets to prevent internal sound reflections. The AR 9 is highly regarded for its dynamic range, low distortion, and warm, natural sound character, making it a classic reference speaker from Acoustic Research's late 1970s lineup.