I'd have said that the subject is "Liza's penchant for playing music at top volume," since that's what the sentence is about, not Malcolm. But, alas, I'm wrong.
Sorry Clary! Guess I need to brush up on my grammar!
But that reminds me of another peeve of mine.
Duane always complains about Sarah going home early.
Duane always complains about Sarah's going home early.
Because, of course, Duane is complaining about "Sarah's going home early," not "Sarah." I hear this often.