(original “A” versions) Loudspeaker Pair, Oiled-Walnut Cabinets, SN A 4516 and A 4628, VG-to-Excellent Condition. Loudspeaker, SN A-4516 & A-4628. This pair of AR-10Pi speakers are the original, early versions built in late-1975 or early 1976, and are finished on all sides in a beautiful oiled-walnut finish. The serial numbers are A 4516 and A 4628. This “A” version of the AR-10Pi is a. More desirable, but less common, version of this series than the later “B” version. This version also has the first iteration yellow-dome. 75-inch treated-cloth tweeter (non Ferrofluid version), and therefore there is no possibility of drying Ferrofluid in these tweeters. The midrange drivers (1.5-inch soft dome) are also non-Ferrofluid versions. The cabinets are in very good-to-excellent condition overall except for some slight marks and scratches, but the speaker look great overall. The back-side of one of the speakers has some slight delamination of the veneer and some veneer cracking, a common problem with the original-series version. “B” versionreally not as elegant a speakerremedied this problem with a different molding around the back of the cabinet. There is a small indentation on the grill molding area, but it is small and not very noticeable. The original, machined-foam grills are still in fine condition, which is very unusual. There is little deterioration (if at all) in these urethane-foam grills, which is remarkable. Both grills are about equal. The operating performance of these speakers is basically perfect. The resonance was exactly 41 Hz for both cabinets, exactly within spec; the woofers’ frequency response measured flat to within 1.5 dB from 38-500 Hz on axis and the harmonic distortion (measured with an HP339A distortion analyzer) for both speakers measured less than 8% at 20 Hz with 20 watts rms input! At 10 watts, the distortion was on the order of 5% down to 20 Hz, and at 1 watt (the “standard” measurement) input, distortion was under 3% down to 20 Hz. In short, the AR 12-inch woofer wasand still isamong the very finest low-frequency reproducers ever designed, and these woofers easily meet that original specification. The midrange and tweeter drivers work perfectly, and the switch level controls for speaker placement “Pi” control contour (autotransformer) work fine. Was introduced on March 17, 1975 as part of AR’s newly announced Advanced Development Division. It was the first speaker of this new series, and it was AR’s flagship loudspeaker during this period, and it has been considered one of the finest loudspeaker designs in audio history, capable of extremely accurate and flat acoustic-power response into normal listening rooms. This speaker was designed to replace the famous AR-3a with improved high-frequency output at the highest frequencies and a smoother acoustic-power response, along with the ability to compensate for different speaker placements within a normal listening environment. The new speaker was a 3-way acoustic-suspension design which featured the new treated cloth-dome. 75-inch dome tweeter and the AR-3a-type 1.5-inch dome midrange and the well-known, industry-leading 12-inch AR-3a woofer design, widely considered to be among the very finest woofers ever designed. No 12-inch woofer design has ever surpassed the AR 12-inch woofer in terms of flatness of response and low harmonic distortion down into the 20-30 Hz region. The new tweeter enabled the AR-10 to produce very flat high-frequency output, surpassing the AR-3a in output extension, and nearly equaling the AR-3a in off-axis dispersion. Derives from the autotransformer crossover (patented by AR, US Patent 4021614) that accurately compensates for the effects on bass energy radiation of Pi, 2Pi and 4Pi speaker placement. These terms refer respectively to placement of the speakers at the junction of two surfaces, such as in a corner or on the floor against a wall, on one wall and out in the room away from all room surfaces. This facility, called “Woofer Environmental Control” by AR, insures that the speaker’s flat energy response characteristic will be accurately maintained under all of these conditions. The AR-10Pi has all controls on the front panel behind a hinged solid-walnut door, a. Very costly engineering detail that adds to this speakers quality. Technical Specifications on the AR-10. 25″ x 14″ x 10¾ (without grill). 55-57lbs net; 64lbs gross. 12-inch acoustic-suspension woofer; 1½-inch dome midrange, ¾-inch dome tweeter. 4-16 ohms nominal, depending on switch positions. 50 watts will produce 100dB in an average room. 86 dB at 1 watt at 1 meter. Woofer-midrange 525 Hz, mid-tweeter 5000 Hz. ½ secton L-C network on each driver with air wound choke coils and Sprague electrolytic, computer-grade capacitors. Energy output controlled by an autotransformer and switching network. Woofer 18Hz, midrange 400Hz, tweeter 2000Hz. Woofer 200,000 maxwells, midrange 70,000 maxwells, tweeter 21,000 maxwells. Woofer 9,800 gauss, midrange 13,000 gauss, trweeter 18,000 gauss. Overall Description covered by. Reproduction or copying of any of this material without the express permission of the writer is unlawful and prohibited. The item “Acoustic Research AR-10 (original A versions) Loudspeaker Pair, Oiled-Walnut” is in sale since Monday, February 08, 2016. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Speakers”. The seller is “acoustic-research-inc” and is located in High Point, North Carolina. This item can be shipped worldwide.
- Brand: Acoustic Research (“AR”)
- Model: AR-10
- Country/Region of Manufacture: United States
- Design: 3-way acoustic-suspension