We already discussed this before on another thread but i will answer you quickly anyway. In Japan the Castlevania sereis is called Dracula X. Since that particular game is called Symphony of the Night the names kinda merge together to specify the series (Dracula (X)) and the subtitle of the particular game in the series ((Symphony) of the Night) using a shorter title. Thus you get Symphony X. Yes the music sounds kind like Symphony X but of course it does when the setting of the game is real gothic like and music is inspired with rock metal and sounds from the baroque period.