Firstly ensure the sample frequency is set to the same throughout your system. Also, ensure that the clock source on the master clock device is set to 'internal'. If you still hear clicks and pops check the 'ADC lock' LED on the VoiceMaster Pro - if it is flickering then the unit is not locking properly to the word clock signal and you should test the word clock source for problems. Try syncing other devices to the master word clock unit to see if the problem continues to occur. Also, it is worth trying syncing the VoiceMaster Pro to a different word clock master device to help narrow down the cause of the problem.
If there are no other digital audio devices in your set up (apart from the VoiceMaster Pro and the receiving device) you do not have to use a BNC cable to sync the VoiceMaster Pro externally and can set your gear up using the VoiceMaster Pro as the clock master instead of the receiving device. Make sure the clock source on the receiving device is set to 'SPDIF in' for this. If you have tried this and there are still clicks and pops present then contact us for further advice.