Hum Created When lav mic connect to jack

[dhruva]

Using a Toshiba Camileo X200, I'm getting a humming sound like a motor running while using an audio-technica ATR3350 lav mic. I checked the mic itself on another device and there was no hum, so I'm assuming the jack or camcorder is the root of the problem. The camcorder works fine from its own internal mic, but when I plugin the mic, the recording reveals the hum....even without the mic being turned on! It makes no difference whether or not the mic is turned on, the hum remains present with no change.

The mic has a stereo jack, but I cannot find spec info about the camcorder receptacle.

Any suggestions are appreciated.

[julitomg]

I have an Audio-technica lavalier mic just like yours and I don´t have any issues when it´s connected to my camcorder other than recording the sound only on one channel (easily fixed in post). The mic itself is mono, not stereo as you mention. The camcorder´s jack is probably stereo. Could it be that the mic doesn´t "seat" or fit all the way it´s supposed to and there´s some kind of short between the tip and ring? You can try to use a mono to stereo adapter (wich is very popular in this kind of setup anyway) like this:
http://www.radioshack.com/product/index.jsp?productId=2102690&filterName=Cable+type&fi...Audio+adapters
Also check if your camcorder has manual audio level control, if it´s always in "auto" it´ll try to boost the volume of low volume sounds including any hum or noise.

[dhruva]

Thanks for the reply. I called my local Radio Shack to make sure they have that adapter, and will pick it up today to see if it helps. Unfortunately my camcorder does not have a manual audio level adjustment. I also checked the way the fits into the jack, and it's as tight and proper as any I've ever seen, so I doubt that's the problem.

[johns0]

Sounds like you might have a ground problem in your camera mic input,easy way to find out is plug the mic in and jump a lead from the mic ground to your camera ground.If it goes away then your mic input has a faulty ground.

[dhruva]

I tried the stereo to mono adapter with no improvement......

As far as " jump a lead from the mic ground to your camera ground".......how do I do that?

[johns0]

Get a wire with a fine lead and connect to the base of the mic and look for a part of the camera that's metal such as a screw to chassis.

[dhruva]

I finally hooked up the suggested ground method, but alas.....the sound still remains. It almost sounds like a small running motor, very steady.


Does anyone have any other suggestions?