Hibiki Otonokoji is the ultimate vocalist.  She has pale pink eyes and lavender hair, which gradually fades to a rosy red color. Her hair is split into two pigtails, with its tips notably curlier than her sister's. Two pink eighth-note hairclips are clipped to each side of her pigtails. She wears a pale blue sailor dress with a light magenta collar and white trim, a large light amber bow, and a pale magenta lining near its hem. On top of this is a long-sleeved dark purple cardigan.