What does it take to make a great string quartet? Certainly technique - just ask any of the groups that don't have it. But also the kind of interpretive spark that will ignite not only an audience but the music itself, illuminating it from within.

Those thoughts, however cursory, are occasioned by the local debut of the Colorado Quartet, Wednesday at the Museum of Fine Arts, whose publicity says they have "been acclaimed on four continents as one of the great string quartets of all time."Without question the potential is there. Except for a somewhat less-than-unanimous final chord in the slow movement of the Brahms Op. 51, No. 2, there was little to fault mechanically in their polished renditions of not only that composer but Haydn and Martinu. But only occasionally did I sense the interpretive spark referred to above.

Certainly not in the Haydn, his Op. 20, No. 2, the second of the "Sun" Quartets, which came in for a serious-minded but comparatively mild reading. Best was the second movement, whose determined stateliness seemed to foreshadow the slow movement of the Beethoven G major Piano Concerto. But that followed a comparatively deliberate opening movement and preceded a final fugue that, for all its clarity, failed to communicate much electricity.

Better in that respect was the Martinu, that composer's Quartet No. 3, from 1928. Clearly influenced by Bartok and, in the semi-nightmarish second movement, Janacek, it is a work well worth hearing. And although again I would not have minded an even more incisive rendition, the unconventional bowings of the first movement registered strongly enough, as did the lyrical flashes that shone through even the agitated dash of the finale.

A word, moreover, for violist Francesca Martin and cellist Diane Chaplin, both of whose instruments are prominently featured in the writing and who handled their assignments with dexterity and restraint.

None of the foregoing served to prepare me for the opening movement of the Brahms, however, which likewise may have been a bit understated but whose nuanced richness and integration not only maintained interest but made sense of the celebrated and much-speculated-upon "F.A.E." note sequence - a reference (possibly) to what may have been an intended dedication to Joachim.

In short, a wonderfully involving account, which again managed to highlight the natural warmth of the viola writing. After that, though, only the semi-mysterious Quasi minuetto approached that standard, the slow movement, despite its subtle interplay, proving considerably less rapt and the finale anything but the last word in gypsy abandon.

Next season the Chamber Music Society of Salt Lake City, under whose auspices this concert was presented, is contemplating the Alban Berg, Borodin, Guarneri, Mendelssohn, Ridge, Vermeer and Alexander Quartets, as well as the Tallis Scholars. At least those were the names on a ballot passed out to the membership Wednesday, any five of whom will guarantee some greatness. But a warning: Should the Berg, the Borodin and the Tallis Scholars not make the cut, they'll have to answer to me!