From their YouTube channel:

“We are a family that loves to sing together and record inspiring and uplifting music. Our music is influenced by classical and fantasy literature as well as cinematic, traditional, religious, and classical music. Being a family, we have the unique advantage of similar sounding voices that blend well together. We also have a very broad vocal range potential of over five octaves with a particular focus on singing in the deeper registers. This all enables us to create well blended recordings with a lot of musical depth. ”