श्रोत्रमेवर्ङ्मनः साम तदेतदेतस्यामृ-च्यध्यूढं साम तस्मादृच्यध्यूढं सामगीयते ।श्रोत्रमेव सा मनोऽमस्तत्साम ॥
In plain words
The ear is the ṛk and the mind is the sāman. This sāman rests upon that ṛk; therefore the sāman is sung as resting upon the ṛk. The ear indeed is sā, the mind is ama, and their combination is sāman.
Close to the Sanskrit
The ear indeed is ṛk, the mind is sāman. That this sāman is mounted upon this ṛk, therefore the sāman is sung mounted upon the ṛk. The ear indeed is sā, the mind is ama, that is sāman.