Acoustic Research AR-11 (1977)
3-way, 3-driver loudspeaker system with updated AR-3a driver technology and adjustable midrange and tweeter levels
Overview
The Acoustic Research AR-11 is a 3-way, 3-driver loudspeaker system introduced in 1977 as the replacement for the AR-3a. It uses updated versions of the same driver designs found in the classic AR-3 and AR-3a, including a substantially improved 305mm (12") acoustic suspension woofer, a hemispherical dome midrange from the AR-3a, and a newly designed 19mm (3/4") high-range dome driver with advanced materials and construction. The AR-11 delivers a smooth, balanced sound with surprising bass output and low listening fatigue, producing a "big beautiful musical sound." It shares many appearance features with the AR-10, including acoustically transparent, precision-machined foam grills that are interchangeable with the AR-10pi and other contemporary AR models.
Specifications
| Frequency Response | 27Hz to 30kHz |
| Impedance | 4Ω |
| Sensitivity | 86dB |
| Power Handling | 100W |
| Recommended Amplifier Power | 25 to 225W |
| Minimum Amplifier Power | 25 watts per channel |
| Maximum Amplifier Power (Conditional) | Up to 150 watts continuous per channel (clipping 10% of the time) |
| Crossover Frequencies | 525 Hz and 5000 Hz |
| Drivers | 1 x 305mm (12") acoustic suspension woofer, 1 x 38mm (1.5") hemispherical dome midrange, 1 x 19mm (3/4") hemispherical dome tweeter |
| Controls | 3-position level controls for midrange and tweeters (3dB steps) |
| Dimensions | 354 x 635 x 273mm (13.94" x 25" x 10.75") |
| Weight | 50 lbs (22.6kg) each |
| Cabinet Finish | Genuine walnut veneer |
| Connections | Terminals accepting bare wire and vintage spades |
Design
The AR-11 uses a new crossover network featuring half-section LC designs with air-core chokes and computer-grade electrolytic capacitors, with switchable resistive networks controlling midrange and high-frequency output. Larger capacitors were added alongside original values for improved performance. The 19mm tweeter features new diaphragm materials, voice coil, and construction, offering brighter high-frequency response to offset reduced dispersion. A foam piece around the tweeter absorbs internal reflections. The system is engineered for uniformly dispersed, flat energy output across the audible spectrum. The easily removable foam grills are acoustically transparent and shared with the AR-10pi.
Context
The AR-11 replaced the AR-3a in 1977 alongside the AR-10pi, maintaining the acoustic legacy of AR’s flagship models while offering a more accessible alternative. It shares driver technology with the AR-10pi, including the improved tweeter and midrange domes, but omits the Woofer Environmental Control system found in the AR-10. Positioned as a budget-friendly option, the AR-11 delivers similar look and performance to the AR-3a with modernized components.
Market
Foam degradation is common: surrounds on woofers and tweeters, as well as foam grills, typically deteriorate with age and often require refoaming using available repair kits. Cabinets are genuine walnut veneer, with condition varying from pristine to repaired or refinished. The model appears regularly on the used market.
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