The opening of a five-movement "Sinfonia concertante" in an expressionist / late romantic idiom for string orchestra. This "Capriccio tenebroso" functions as a modified sonata-allegro form in itself, as well as an exposition of sorts for the work as a whole, preceded by a slow introduction wherein fragments of later-to-be-established motivic/melodic ideas "rise out of the ether". Past the introduction, within the movement proper, a perpetually unfurling contrapuntal texture often anchored in the exotic Lydian dominant (Lydian + Mixolydian) and Whole Tone scales accumulates tension, all sense of tonal gravity frequently suspended, leading to an intensely energized and dramatic concluding passage.
You may find the engraved "conductor's score" here.
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