I first met Grumiaux in his classic recordings of Bach's Violin Concertos. The natural freshness of his playing is an experience. He never tries to add sweetness to the beautiful slow movements. His bow is always full and glorious. His playing comprises a classical sunlit quality which is particular suitable for the music of Bach and of course Mozart.
It was said that Grumiaux possessed the gift of absolute pitch. Too many would take his immaculate technique too easily. Indeed, in this Belgium, we find the perfect representative of the Belgium-Franco school. The sensitivity and naturalness of his playing could only come from a cultured master. I still find his Bach's playing his crowning achievement. The springing rhythm and bowing variety in the fast movements of BWV1041-1042 is only possible with his effortless virtuosity. The brilliance and richness of his tone can be best appreciated in the opening movement of BWV1042. In the repeated notes, the solo violin floats on top of the support of the orchestral. The slow movements are more reserved than the much slower playing by Perlman. But the mastery bowing of Grumiaux brings out the meditative quality more successfully with a rich variety of progressing moods.
Grumiaux also recorded a set of Mozart's violin concertos. This is a classic set. To pick from it, I would choose No.3 and more specifically its opening movement. His Mendelssohn and Brahms should also be placed among the very best. His Tchaikovsky is very special indeed. With more than sufficient technique to light up the firework in this work, he chose to highlight the poetry of this warhorse concerto. The middle section of the finale movement is particularly moving. (I have heard a live performance by Cho-Liang Lin which opted for a similar approach, but the overall control was far superior.) Grumiaux's account of Beethoven is polished and cultured, but lacking the last degree of inspiration as in the account of Szeryng. His recordings of sonatas by Bach, Beethoven, Brahms and Faure also enjoys cult status.
It is an age which encourages extrovert display. Less room is reserved for cultured artists like Grumiaux. His name is only admired in a small circle of connossoires. I believe Grumiaux should at least enjoy the same degree of fame as an Oistrach.