"Who is the voice of this band?"
Translation:Care este vocea acestei trupe?
To say someone is "the voice" of something means that they represent it publicly. In other words, "the voice of the band" would be the member of the band who did most of the interviews etc. Somehow I doubt that's the intended meaning here.
If this is meant to refer to the person who sings, then we'd say something like:
"Who is the singer/lead vocalist in the band?"