Complex sentence: The mixing of the recordings also used more modern techniques: overdubbing, a technique used by recording studios to add a supplementary recorded sound to previously recorded material; and doubling, where the vocal line used is sung twice.
Split into simpler sentences: The mixing of the recordings also used more modern techniques such as overdubbing, a technique used by recording studios to add a supplementary recorded sound to previously recorded material. The band also used a technique known as doubling, where the vocal line used is sung twice.