Acoustic Research AR-4X, Vintage Bookshelf Loudspeakers

Introduced around 1966 as an improved successor to the AR-4, the Acoustic Research AR-4x established itself as a benchmark for high-fidelity, compact, 2-way loudspeaker systems. Its design utilizes an acoustic suspension system, featuring a 0.654 cubic foot sealed, fiberglass-filled enclosure that houses an 8-inch woofer with a distinctive treated cloth surround. This configuration, utilizing the air within the sealed cabinet as a restoring force, allows for excellent, low-distortion bass extension despite the speaker's modest size.

Its 2.5-inch wide-dispersion paper cone tweeter was a significant upgrade from its predecessor that allowed for a smoother, more extended high-frequency response. Crucially, the crossover frequency is set low, at approximately 1200 Hz. This design choice bridges the gap between the 8-inch woofer and the tweeter, maintaining an exceptionally smooth power response in the critical midrange, effectively preventing directional effects common in other 2-way designs of that era. The crossover network is relatively simple, typically consisting of an inductor and a capacitor, though it provides effective separation, ensuring that the 2.5-inch tweeter remains well-integrated with the woofer.

The AR-4x quickly became a highly respected, cost-effective option for audiophiles and professional musicians. It frequently outperformed larger and more expensive competitors in laboratory tests, such as those conducted by Consumer Reports in 1966.

While requiring a decent amount of power to achieve high output levels—due to the lower efficiency of the acoustic suspension design—the AR-4x provides deep, tight, and natural bass that remains iconic in vintage audio circles. Its robust design, featuring quality drivers and a substantial cabinet, has helped it maintain its reputation for excellent sonic performance over many decades.

This example has undergone our full restoration treatment.  Crossovers have bene refreshed with a new capacitor, replacing the tired Chicago Condenser unit originally supplied.  The drivers have all been tested for performance and deliver exactly the smooth response one would expect from this classic system.  The original walnut wood veneer was resurfaced.  Finally, the grille cloth was replaced with our own poly-linen blend for acoustic transparency.  

Test drive these amazing, compact vintage bookshelf speakers.  Paired with a modestly powered tube or solid state amp, they are a real treat.

$399/pair (plus applicable shipping and/or MA sales tax)