Audio level automically lowered when using 2 external mics and one is dominate

R

Ron Fong

New member
I have a dvx100b with two external mics (both phantom powered) connected to inputs-1 and input-2. Both mics are Okatava MK012. I switch on mic connected to input-1 and set the volume level so I get 2-3 red bars on the audio channel meter. This is my reference volume for that channel and the mic is attached to the camera. Everything is OK as long as I only have this one mic turned on. My problem starts with I turn on the mic connected to the other input (input-2).

The Mic on input-2 is on a 20 foot xlr cable positioned on a boom directly above my audio source. As soon as I turn on input-2 and have dialog coming through it, the volume meter strength on input-1 suddenly drops off significantly. Behavior is as follows: once one of the mics is the dominate mic (when it receives a significantly louder audio source) then the camera automatically lowers the volume input on the other mic. Then when I turn off Mic on input-2 or distance it from the sound source, the meter strength on iput-1 automatically returns back to my reference level.

When I place both mics side by side so they are receiving the same relative audio source strength, turning on the second mic on input-2 does not seem to affect the volume level meter strength for the mic on input-1's channel. I am assuming this is because neither mic is dominate.

Can anyone help explain the unusual behavior I am experiencing when connecting two external mics and one channels volume level is automatically lowered when a 2nd mic becomes dominate in terms of receiving a louder audio source?
 
Turn off ALC in the menu. It would have an effect much like that. Do the audio level pots have any effect on the signal you're recording?
 
Thanks Angus, ALC was causing my problem behavior

Thanks Angus, ALC was causing my problem behavior

Thanks Angus, it was the MIC ALC that was causing the problem behavior I was experiencing. Once I set MIC ACL to 'off' my problem behavior went away. Unfortunately ACL seems to act on both channels at the same time even when it is only one channel that is being overdriven. Thus ALC was causing the channel that had just the right volume to be suddenly lowered when the other channel got to hot of a signal'.

But now, by turning ALC 'off', this presents a different problem in that I will now have to more closely monitor the audio levels to manually control high volume level distortion now that ALC is 'off' and not protecting me.

Since I would prefer to have ALC 'on' when using external mics attached to input 1&2, I will do some experimenting with trying to balance my mics so that I can have ACL 'on' and reduce how often ALC kicks in triggered by a dominate mic (with a signal too hot). I'll try using a combination of 'MIC Gain' and adjusting volume output coming from my wireless lapel mic.

If anyone else out there has some comments on this topic, please jump in.

Thanks
 
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