Boisterous sons to explain access for improving PC facilities (9,4)
I believe the answer is:
expansion slot
'access for improving pc facilities' is the definition.
I know nothing about this answer so I can't tell whether this works.
'boisterous sons to explain' is the wordplay.
'boisterous' indicates an anagram (I've seen this in other clues).
'sons'+'to'+'explain'='sonstoexplain'
'sonstoexplain' with letters rearranged gives 'EXPANSION SLOT'.
Can you help me to learn more?
(Other definitions for expansion slot that I've seen before include "Port on computer motherboard" , "Space for computer plug-in" .)