The Acoustic Research AR-4X Book Shelf Speakers are a vintage audio gem that embodies the classic sound quality and craftsmanship of Acoustic Research. Known for their sleek design and powerful performance, these speakers are a popular choice for audiophiles looking to add a touch of nostalgia to their audio setup. With their timeless appeal and reputation for delivering exceptional sound, the Acoustic Research AR-4X Book Shelf Speakers are a must-have for any vintage audio enthusiast. Technician checked all units and crossover circuit and replaced tweeter level control attenuators with new one for both pair.