Sibelius had long disliked the sound of orchestral music as it played on the radio of his time. The fidelity and frequency range was limited, cutting off a lot of the lower instruments and enhancing the higher ones. The thought of composing music that would better fit the playback limits of the radio was one innovation that Sibelius employed in a number of his works as many performances were broadcast instead of recorded.
The Andante Festivo was originallly scored as a string quartet on the occasion of the 25th anniversary of the Saynatsalo plywood mill in Finland. Sibelius later arranged the work for string orchestra and timpani, to be broadcast on New Year's Eve 1939 as a greeting to the world at the World Exhibition in New York. And it is the only recorded work of him interpreting his own work.
I set this lovely work into three different forms as it became apparent that it would work. The entry is in Finale 2008 and uses the CMB library.