For sale is a pair of RARE Classic. Acoustic Research Holographic Imaging series M4 Floorstanding 3-way. These do sound Amazing! They are in nice condition only minor wear, there are no major scratches no cracks or breaks, they are a dark gray matte finish. The speakers have no dents holes rips or tears, the grills are also nice and clean no holes rips or stains and the frames have no cracks. They have never been over powered and have a small footprint for easy placement. There is no buzzing or distortion, All drivers are fully functional. They are nice and clean no odors and come from smoke free home. Please see photos for complete details. The Acoustic Research Holographic Imaging Series of loudspeakers was designed to create a more natural and believable sound stage, or stereo image, than conventional speakers do. To achieve this effect, all six models in the series have the driver that handles the musical midrange at the top of the cabinet, angled upward at about 30 degrees. The tweeter is just below that driver, offset a few inches to the outside, so that the tweeters are spaced slightly farther apart. According to AR, the upward-firing drivers provide improved hall-simulating midrange reverberation through ceiling reflections. The output from the tweeters slightly favors the inward direction, toward the listening area, creating a clear center stage in the sound field. Three speakers in the series are designed for installation on shelves or stands, and three are floor-standing models. The M4, the smallest of the floor-standing speakers, is a three-way system in a slim, compact cabinet that measures 7-3/4 inches wide, 10-1/8 inches deep, and 28-1/8 inches high. The cabinet leans slightly backward to tilt the tweeter radiation a few degrees, making the overall depth from top rear to bottom forward edge about 15-1/4 inches. Each speaker weighs about 23 pounds. The upper half of the cabinet is a sealed acoustic-suspension enclosure for the 6-inch bass/midrange driver, whose carbon and mica-filled polypropylene cone has a 32-Hz free-air resonance. The driver’s response is allowed to roll off naturally at low frequencies. At 3,600 Hz there is a crossover, with 12-dB-per-octave slopes, to the 3/4-inch soft-dome tweeter, whose voice coil is cooled by ferro-fluid. The lower half of the cabinet contains a separate sealed enclosure for the 6-inch low-bass woofer, which is mounted upside-down at the cabinet’s bottom, with its basket and magnet external to the sealed cavity. This arrangement is claimed to provide more effective cooling of the voice coil when it’s operating at high levels, since air can flow over the metallic parts of the driver. The sealed cavity, like the tweeter’s enclosure, is filled with sound-absorbing material. Although the woofer is the same size as the midrange driver, it has a relatively massive paper cone with a free-air resonance of 28 Hz, and a series inductor rolls off its output above 100 Hz. The output below 100 Hz emerges from two rectangular ports on the sides of the enclosure. The two cone drivers have different low-frequency resonance, or “Q, ” characteristics, as well as different resonant frequencies, so that their outputs combine to produce a strong, uniform response down to 50 Hz. The speaker is recommended for use with amplifiers designed to drive loads of 4 to 8 ohms and with power ratings of 20 to 150 watts. The AR M4 is finished in charcoal-gray vinyl. I do take pride in packaging and I will pack with great care at no extra charge, poly bags, edge protector, bubble wrap, shrink warp, styrofoam double boxes etc. Thank you for Looking, Chris. Get images that make Supersized seem small. Track Page Views With. Auctiva’s FREE Counter. The item “2 RARE ACOUSTIC RESEARCH AR HOLOGRAPHIC IMAGING M-4 SPEAKERS XCLNT MAIN VINTAGE” is in sale since Wednesday, February 12, 2020. This item is in the category “Consumer Electronics\Vintage Electronics\Vintage Audio & Video\Vintage Speakers”. The seller is “chrisw1740″ and is located in Tampa, Florida. This item can be shipped to United States.