Interesting fact: the mellotron uses taped sound samples, with one magnetic audio tape assigned to each key. Each tape is eight seconds in length, and plays when you press its respective key.
It makes a really strange scratching noise when something's wrong with the tape. Otherwise, it sounds like whatever is recorded on them.
So "the scratching of a mellotron" doesn't really refer to the sound; it refers to any blatant sign that something's not working properly. That's what's upsetting her.
Also, interestingly, the character of David works in sound design, and probably uses the mellotron in his work. Meaning that the evidence of malfunction/dysfunction may have something to do with his job... perhaps, very literally, a mellotron with a worn-out or caught tape.
Interesting fact: the mellotron uses taped sound samples, with one magnetic audio tape assigned to each key. Each tape is eight seconds in length, and plays when you press its respective key. It makes a really strange scratching noise when something's wrong with the tape. Otherwise, it sounds like whatever is recorded on them. So "the scratching of a mellotron" doesn't really refer to the sound; it refers to any blatant sign that something's not working properly. That's what's upsetting her.
Also, interestingly, the character of David works in sound design, and probably uses the mellotron in his work. Meaning that the evidence of malfunction/dysfunction may have something to do with his job... perhaps, very literally, a mellotron with a worn-out or caught tape.