Trains too loud for the GL2 microphone?

Hello everyone,

I often use my GL2 to shoot video footage of trains. I am one of those railnuts/railfans that you may see trackside every once and awhile.

Anyways, I am extremely pleased with the image quality of the GL2 but the audio is driving me crazy. Whenever I shoot footage of a locomotive and the train blasts it's horn, the audio becomes very distorted. I have tried adjusting the manual audio levels, but the audio peaks no matter what. On playback the audio "pops".

Is an external mic my only option, or is there some way I can resolve the problem? If I need an external mic, is there an affordable model that is recommended for the type of shooting I am doing?

Thanks very much for any advice.

Have you turned on mic attenuation (MIC ATT On) in the menu? That will cut the signal voltage by a factor of ten, which will help with many loud sounds, but there is a limit. You will still probably have to record "normal" sounds like conversation at very low levels with your manual adjustments to leave room for the train's horn.

For a 110 decibel horn, a microphone will put out about 1000 times the voltage it puts out for 50 decibel conversation.

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Fred

Thanks Fred,

I have turned on the Mic ATT and will give it a try this week.

I will also use the Manual audio control buttons on the side of the camera.

Would a microphone such as the Rode VideoMic help in a situation like this one, or would the audio still be VERY loud for the GL2 to handle?

Thanks again,

Eric

Eric,

There are three ways to get clipping (distortion of loud sound). One is for the mic to be overloaded by the sound. The next is for the camcorder input circuit to be overloaded by the mic output. The last, and the only one indicated by the meters, is recording at too high a level. You can get clipping from the first two and adjust the levels to record the mess at the proper levels and the meters will look fine. That's why we always wear headphones when recording.

The Rode VideoMic has a maxium input sound level of 134 dB. That will handle the train horn, but it will put out a signal that's likely to clip the input.

I use a BeachTek adapter with a built in limiter between my mic(s) and the GL2's mic input. A limiter is circuitry that protects from clipping due to loud sounds.

--
Fred

The Rode VM has DIP switches that reduce the strength of the signal the mic sends to the recorder. Those should help you considerably in keeping your levels below the red line. I wouldn't think a train recorded at a distance would cause the Rode to brick wall (overload the mic) but the Rode puts out a strong signal unless the attenuators are used.

If you use a Rode and you still get distortion after turning the DIP switched to their lowest level then I would suggest covering the mic in a layer of foam to reduce the amount of sound that reaches the element of the mic. This may cause some frequencies to be attenuated more than others though so I would only try this as a last resort.

Thanks for the advice everyone!

Eric