The left-hand group shows eight fair haired angels wearing crowns and gathered in front of a music stand singing, although none of them looks towards the score on the stand. As in a number of the other panels, here van Eyck used the device of the open mouth to give a sense of life and motion to his figures. Borchert writes that the emphasis on the open mouths is "specifically motivated by the desire to characterize the angel's facial expressions according to the various ranges of polyphonic singing. To that end the position of the angel's tongues are carefully registered, as are that of their teeth." Art historian Elisabeth Dhanens notes how "One can easily see by their singing who is the soprano, who is the alto, who is the tenor and who is the bass".