Arcane inquiry re 1960s speakers ad

Im not sure if this is the appropriate forum for my inquiry, but I wonder if anyone in the audiophile fraternity can answer a trivia question about a print ad I saw in more than one issue of High Fidelity (and perhaps Stereo Review also) in the late 1960s. It was a full-page advertisement for speakers -- the company I cannot recall, but it was among the leading names in stereo components during that period -- featuring a stylized color drawing of ten famous classical composers standing together in a group. Beethoven was in front, holding an ear trumpet, with a cartoon balloon above his head saying "WAS?" (German "What?). The other figures were arrayed beside and behind him and were instantly recognizable to music lovers -- as I recall, they were Bach, Handel, Mozart, Haydn, Schubert, Schumann, Wagner, Brahms, and Tchaikovsky.
The caption underneath said something along the lines of "9 out of 10 listeners tested" endorsed (or some similar term of approbation) the excellent sound quality of the product. Beethoven was obviously unable to do so, and was hence the outlier. Does this description ring a bell (sorry, Ludwig) with anyone? If not, can you refer me to any possible online source of such perversely arcane data? I would like to know which company's ad this was, and ideally which issues of High Fidelity (or other periodicals) might contain it. I will not be deaf to any information which may be offered.