The two musical panels are commonly known by variants of the titles "Singing Angels" and "Music-making Angels", and are both 161 cm × 69.3 cm. Each features a choir; on the left angels gather behind a wooden carved music stand positioned on a swivel, to the right a group with stringed instruments gather around a pipe organ, played by a seated angel, shown full-length. The presence of the two groups on either side of the Deësis reflects a by then well-established motif in representations of the heavens opening; that of musical accompaniment provided by celestial beings. As was common in the Low Countries in the 15th century, the angels are dressed in liturgical robes, a custom that migrated from Latin liturgical drama to the art of the period.