Siren magic isn’t natural, it’s supernatural. The voices heard are quite simply the result of channelling their inner magic to their victims through a connection. The best example of this would be a unicorn casting a spell using its horn. This is why the gemstones are so precious to the Dazzlings, as they do the same thing.

But supernatural magic like this, on its own, is inherently flawed. It is powerful, undeniably so, but vulnerable to attack via counter spell. To prevent this, a naturally powerful singing voice can be introduced as a failsafe, to give the spell all-round invulnerability. Natural power none of the Sirens possess.

Aware of this, Adagio must consider inducting a fourth member to the Dazzlings. Preferably a lost soul, easy to manipulate, someone who will be unable to resist the power of a Siren amulet, but can sing without it just as well.

She may have found her perfect candidate.