Israel Festival JSO Mozart Masses Jerusalem Theater June 6 Mozart's Requiem, by itself, is commonly a full-length concert program. The addition of Mozart's Coronation Mass and his Mass in C minor may seem to be too much of a good thing for one single concert. Fortunately, however, it turned out to be a splendid performance that made one oblivious to the passing time. Marco Zambelli, who conducted the Jerusalem Symphony Orchestra, the Collegium Vocale Leoben and the Tel Aviv Philharmonia Choir, held his musicians firmly in his grip and, moreover, adopted brisk tempi that injected a dramatic, almost operatic impact into the works without impairing their spiritual quality. This was a welcome change from the conventional ponderous slow-motion speed with which these works are frequently performed for the sake of supposed solemnity. The result was a lively, intense rendition that was highly impressive and exciting. Outstanding among the soloists was soprano Adina Aaron. Her bright, enchanting voice soared radiantly above the orchestra and choir. This is a rare case of an excellent opera singer who is also capable of capturing the spirituality and devotion of sacred music. Her rendition of the murderously difficult "Et incarnatus est" in the C minor mass was a highlight of the performance. The combined choirs sounded well consolidated and displayed strong contrasts with subtle shades of gradually increasing and decreasing volume. It blended perfectly with the orchestra and its finely polished solo passages.