Tubing that is partly interfering with pianos? (4)
I believe the answer is:
pipe
'tubing' is the definition.
(pipe is a kind of tubing)
I can't explain the remainder of the clue.
(Other definitions for pipe that I've seen before include "Tube for conveying gas or liquid" , "Tube; wind instrument" , "Duct; briar" , "Tobacco is smoked in it" , "Tube to carry water, gas etc" .)