Acoustic Research AR18 .. anyone know of them ?

Sure do-I had two pair-they were my college dorm speakers, way back in the fall of 1978. They were ARs first vinyl-veneer covered speaker. They were slightly smaller than the otherwise identical 17s-which were in turn a cosmetic (and slightly improved) version of the older AR7. All were acoustic suspension, of course-mine worked until 1996. They made various versions of it-improving the efficiency, and other things (mine had foam grills-later versions-'b' and 's' into the very early 1980s-went with nicer cloth grills). If you find some old 1977-1978 magazines, you'll see an ad AR did, putting these speakers next to their large, floor-standing AR9s, and titling them 'Mutt and Jeff.' They were pretty good, played through mostly mid-fi 1970s integrated amps and such-I had them equalized like crazy. Relegated them to bedrooms, backs of cars in parks, etc. Mine held up nice-foam now rotted out-I keep them in my kitchen just as a nostalgia piece. If they still work-enjoy! By the way-the cost was 130.00 a pair, moving up to 145.00 a pair by 1980.