From Wikipedia:
"HB is a Christian symphonic metal band, formed in Forssa, Finland in 2002. They recorded a demo, four albums in the Finnish language with English versions for three of them, two singles, and a live DVD filmed at the Festival Maata Näkyvissä (2006).
Concerning the origin and meaning of the initials HB, Johanna Aaltonen said at the official website of the band: "Actually the initials H and B don't really stand for anything. We once had a competition on our webpage, where people could suggest different meanings for the two letters. Holy Bible was one of the suggestions."
Musically the band is like Nightwish, symphonic metal in style with powerful sounds of the guitars, bass and drums, fused with characteristic instruments of classical music, choir and even a few verses of lyric singing. The band is also characterized by the strong spiritual content in their Christocentric lyrics."