grahamat

It's a Cobra HDTVI 8 DVR The noisy mics have the same noise irrespective of which audio channel they are connected to on the DVR and the two good mics are good on all channels too.

Hi all. I would greatly appreciate it if someone, anyone, could help me with an audio problem I am having on an 8 Channel TVI system. I have posted an audio clip of the noise I am getting on 4 microphones in this sytem on youtube at this link; You will have to copy the link and paste it into your browser I'm afraid as, strangely, the forum doesn't allow uploading of audio files! The setup is as follows; 8 X Twilight TVI mini dome cameras 1 X Cobra HDTVI 8 DVR 6 X standard CCTV microphones 2 of the microphones are absolutely fine and sound as clean as a whistle. The other 4 all make the sound in the clip even though they are also picking up the audio they are meant to. 2 of the noisy mics have a run of around 15 metres and the other two noisy ones have a run of around 20 metres. The 2 clean mics run 18 metres each. None of the cables run alongside mains and all mics are run from the camera point in outdoor grade OFC single screened cable. All mics are fed 12volts from a DC splitter cable mounted in a plastic case which the camera is mounted on. I am about at my wits end with this! The customer isn't impressed at all and I have to say I don't blame him! Any help or advice anyone can offer would be most gratefully accepted. Thanks