Hibiki is one of the main characters and the protagonist of Symphogear who wields the relic known as Gungnir. Hibiki is outgoing, friendly, and overwhelmingly optimistic. While she is a formidable fighter in hand-to-hand combat, she prefers to seek a more peaceful solution to conflicts as much as possible. However, while she does her best to be positive, she has moments where she tends to be sensitive on certain topics, such as her past or she has moments of self-doubt brought about through her various fights within the show. Despite this, she tries her best to be a positive person (even if she has to fake it to do so).

Example of Hibiki's JP VA, Aoi Yuki: (Hibiki at school)

As for the idea of how I feel like she would sound in English, I feel like her voice would be somewhere along the lines of Claudia Lenz's Kana from Fire Emblem Fates (Female Kana example) and her voice for Sumia from Fire Emblem Awakening (Sumia example) (Both voices are from Fire Emblem Heroes)

However, feel free to share your own idea of how Hibiki would sound.