Applies to: RLN8-410; RLN8-410-E; RLN16-410
Please kindly note that NVR only has audio output when it connects monitor via HDMI port, the resolution of the monitor/TV should be 1920*1080 or 1080*720, or the NVR will not have a sound output if the monitor/TV has other resolution used.
Then please kindly refer to the steps below, check whether you have enabled the audio.
Step 1. Go to Menu->Display->Output, make sure the audio output of the NVR is enabled like the picture below. Please check the Audio box in the picture.