Island noise interrupting end of wondrous song (8)
I believe the answer is:
Here is my best explanation:
'island' is the definition.
(Sardinia is an example)
'noise interrupting end of wondrous song' is the subsidiary indication.
'noise' becomes 'din' (din is a kind of noise).
'interrupting' indicates putting letters inside.
'end of' suggests the final letters.
'song' becomes 'aria' (aria is a kind of song).
The last letter of 'wondrous' is 's'.
'din' going within 'saria' is 'sardinia'.
(Other definitions for sardinia that I've seen before include "Adrian is seen in Mediterranean island", "Island belonging to Italy", "Island south of Corsica", "Large Italian island, capital Cagliari", "Is Adrian on the island?", "Second-largest Mediterranean island, after Sicily" and "Corsican neighbour".)