Some musical styles focus on producing songs and pieces for a live performance, while others focus on producing a recording that mixes together sounds that were never played "live." Even in essentially live styles such as rock, recording engineers often use the ability to edit, splice and mix to produce recordings that may be considered "better" than the actual live performance. For example, some singers record themselves singing a melody and then record multiple harmony parts using overdubbing, creating a sound that would be impossible to do live.