I can't say. I know that weather magic also involves whistling, but 'death metal' isn't a kind of music I know of- do you have any recordings I could listen to?

[Somehow, that doesn't surprise Sabriel, although it is concerning- and reminiscent of Free magic's ability to corrode some spells.]

True- Remi was able to seal an orb, but he also had access to one for nearly a decade- he had plenty of time to study it. And even then, he couldn't stop it from making bargains.