Paradisi Porte - Hans Memling's Angelic Concert

Around 1490, the painter Hans Memling created his "Concert of Angels". It consists of three paintings for the outside of an altar and shows God the Father surrounded by angels singing and playing instruments. What might the music have sounded like that inspired Memling to this painting? Very precisely, the painter depicted the instruments of his time, grouped into the "alta" and "bassa capella" typical of the period - the loud and the quiet instruments.