Cleave systems for separating bonded wafer structures, mountable cleave monitoring systems and methods for separating bonded wafer structures are disclosed. In some embodiments, the sound emitted from a bonded wafer structure is sensed during cleaving and a metric related to an attribute of the cleave is generated. The generated metric may be used for quality control and/or to adjust a cleave control parameter to improve the quality of the cleave of subsequently cleaved bonded wafer structures.