Complex sentence: In April 2011, Soundgarden announced a summer tour consisting of four dates in July, and was also headliner for Voodoo Experience at City Park in New Orleans Halloween weekend 2011.
Split into simpler sentences: In April 2011, Soundgarden announced a summer tour consisting of four dates in July. Soundgarden also was headliner for Voodoo Experience at City Park in New Orleans Halloween weekend 2011.