Complex sentence: Their "Students Repertory Theatre" in a loft on Northport's Main Street was large enough to seat an audience of 25; their audiences were appreciative and enthusiastic, and the house was sold out for every performance.
Split into simpler sentences: Their "Students Repertory Theatre" in a loft on Northport's Main Street was large enough to seat an audience of 25. Their audiences were appreciative and enthusiastic; the house sold out for every performance.