Elders, the

The "elders" make their appearance in "Peter Quince at the Clavier" in teh following lines:
"...What I feel.../ is music. It is like the strain Waked in teh elders by Susanna...." (i.5-9).
"She bathed in her still garden while the red-eyed elders, watching, felt the bases of their beings throb" (i.11-13).
"They wondered why Susanna cried/ Against the elders by her side...." (iii.3-4).
"Susanna's music touched the bawdy strings / Of those white elders...." (iv.11-12).
==Who are the Elders?==
This is actually rather ambiguous. Certainly, the elders are treated as a group of elderly men whose libidos are aroused by watching Susanna as she bathes. However, there may also be a pun at work here. Susanna, it turns out, is bathing out of doors, in a garden spring. So it is possible that the elders here are, in fact, trees of the Elder variety. 
==What are the Elders Doing in this Poem?==
On one level, the elders are simply voyeurs. They are Susanna's presumably unseen audience, awakened to an appreciation of beauty, as well as to sexual desire, by their vision of her bathing.
However,  if one reads the elders as trees rather than men, then the scene loses its titillating aspect and becomes more purely Romantic, as Susanna's presence, like that of the Romantic poet, awakens the ecstatic sublime in nature itself. This reading holds even if we imagine the elders as men, since the Romantic poet is someone, by dint of her imagination, infuses nature with the sublime and, what is more, can translate her sense of the sublime to others. In this case,  one would have to understand the elders as readers stirred to an ecstatic encounter with the sublime by Susanna as poet/artist. Thus the poem comes to reflect both the spirituality and sensuality made possible through an encounter with poetry.
Of course, it is also possible that Susanna may play the role of artistic muse, the object of the poets' gaze and thus an extension of the natural world, or perhaps of the "othered" noumenal world. Here, the elders mirror Stevens himself, spurred toward an erotic sublime that, by dint of Susanna's close ties to nature (again, she is bathing outside) is Romantic in a double sense.