Acoustic Research Classic SRA Model 30 Start Price USD 1,500.00 Current Price USD 1,500.00 Time Left - Bid Count 0 Buy It Now Price - Reserve Price - Start Time Sunday, October 05, 2008 End Time Friday, October 10, 2008 Location Randallstown, MD See more about 'Acoustic Research Classic SRA Model 30' Description Classic SRA Series speaker systems are all build around one of AR’s core technology modules, called the Symmetrical Radiation Array (SRA). This “building block” came along after AR’s engineering staff conducted extensive reviews of all aspects of loudspeaker design and manufacture.  Having enjoyed great success with the novel “mid over tweeter” drive unit topology employed in the Holographic Imaging Series,  placement and integration of drivers assumed top priority. What the designers were seeking was controlled, uniform dispersion within a moderately wide listening window, as distinct from the ultra-wide window offered by Holographic Imaging systems. In addition to controlled dispersion, the designers were seeking better integration between mid-band drivers and tweeters.  The result is the SRA, featured in the Classic series of home loudspeaker systems. The SRA consists of four major pieces, one 1” soft-dome tweeter, two midrange drivers and a crossover. Apart from one changed in driver size, the SRA is identical in all Classic systems, from the 18 to the 36. The SRA places the midrange (or mid-bass) drivers above and below the tweeter in a vertical array, at position dictated by the crossover. This topology creates a virtual point source, i.e., all sound appears to emanate from one point (or acoustic center). This has long been the goal of loudspeaker manufactures and there have been many interesting approaches to the problem, co-axial, co-incident etc. The Acoustic Research SRA overcomes most of the point sources without recourse to horns, or waveguides. The output from the midrange drivers must blend seamlessly with that of the tweeter (and with the woofer(s) in the three way systems) so the crossover must divide the signal electrically, and combine acoustically. The design of the crossover considered the three drivers as part of the circuit, and extensive computer modeling was employed to replicate the dynamic performance of the system.   The Classic SRA speakers provide for bi-wiring / bi-amping at the crossover point from woofers to mid-band driver (200 Hz).  Acoustic suspension is the low frequency loading method employed in the SRA series as it still offers the most linear method of producing low frequencies, irrespective of amplitude. The two woofers are used in a vertical array, but are separated by the SRA. Placing one woofer at the top of the cabinet and one at the bottom reduces the chances of exciting nodes in the listening environment as the path lengths to any given point very rarely coincide. This reduces the upper bass congestion prevalent in many floor standing speakers, while retaining the weight and transient impact present in live music. All the cone drivers employed in the Classic series feature the cast-brackets, rather than the more common, and significantly cheaper, pressed steal type. This reduces vibration in the drive unit itself, providing a more stable environment for the moving parts.  The tweeter is an all-new soft cloth dome design with 1” (2.54 cm) voice coil with liquid cooling for improved power handling. The enclosures that house all this technology are designed to be as inert as possible. Trapezoidal in footprint, and with a sloping top, the cabinets are heavily braced internally and are finished in high-quality real wood veneers.  The trapezoidal shape help to reduce the standing waves within the enclosure and provide increased rigidity.  The front panel (baffle) is as slim as possible for any given drive unit size and is heavily reinforced. This is to reduce early reflections in the mid to high frequency domain.  <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Cabinet has scratches, Grilles have snags.  Cones perfect!!!  Each speaker weighs about 75 - 85 pounds. Buyer arranges for UPS (or other prefered shipper) to pick up and deliver pair of units. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Place a Bid!