Personal Sound Zone (PSZ) allows listeners to enjoy their individual sound without being disturbed by sound from other zones. Acoustic contrast, signal distortion, and array effort are the most frequently used metrics for measuring the performance of a PSZ system. However, usually, the three metrics cannot be optimized at the same time. A trade-off between the three metrics has to be made when designing a PSZ system. In this paper, two generalized methods based on multi-objective optimization are proposed for dealing with all possible trade-off problems between the three metrics in PSZ. Optimality analysis of the two proposed methods is taken, and the relationship between the two proposed methods is investigated. Numerical simulations are presented to validate the efficacy and flexibility of the two proposed methods.