Unknown poem Lowry perhaps sings (6)
I believe the answer is:
yodels
'sings' is the definition.
(yodeling is a kind of singing)
'unknown poem lowry perhaps' is the wordplay.
'unknown' becomes 'y' (algebra).
'poem' becomes 'ode' (ode is a type of poem).
'lowry perhaps' becomes 'LS' (LS Lowry).
'y'+'ode'+'ls'='YODELS'
(Other definitions for yodels that I've seen before include "Sings Alpine-style" , "Sings like Swiss mountain dwellers" , "Sly ode (anag.)" , "Sings like a Tyrolean on a mountain-top" , "Sings songs in the Alps" .)