I have just purchased a Nextbase 512G dash cam. Whilst I am more than pleased with the video quality, I am having some problems with sound. There is a vibration type sound recorded with the normal soundtrack. It's more pronounced when the car is on rough roads. I took the unit back to Halfords who swapped it out with a different one, and it has the exact same problem. I have tried it in 2 different vehicles in case there was any electrical interference (long shot), and its the same in both vehicles. The mount is very secure and there is no movement in the dash cam, and nothing rubs against it to cause the vibration. Has anybody experienced anything similar with these cams or does anyone have any suggestions as to what may be causing it?