Yes, the DVRs can record audio from one channel only. To do this, connect an amplified microphone to the mic jack on the back of the device and go to the settings page to activate the channel you want.
How to activate Mic recording:
1) Log into your EZVIZ DVR device settings page
2) Click Advanced Settings
3) From the Record menu option, click Parameters
4) Select the camera you want audio for and to activate it
5) Scroll down to stream type
6) Select the Video and Audio options and click Apply.