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Old July 26th, 2006, 09:16 PM   #1
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lav mic distortion on talking head

Hi all,

I have a Telex ENG100 wireless system that is new to me. I did a few tests, adjusted levels, etc, and it sounded great (diversity receiver, XLR connections). Then I used it on a series of interviews for a video I'm doing.

Suddenly, with one of the guys, I'm hearing distortion although his voice is not particularly loud, the levels on the camera (Z1) are nowhere near peaking, and the mic output to the receiver is not even making the peak metre on the receiver light up. The manual suggests setting the mic level on the transmitter so that the peak metre on the receiver barely lights up, but when I try that, it seems incredibly hot, so I was below that.

Any suggestions why I might be getting this distortion? I'm pretty useless with audio, as I find it incredibly confusing, but I'm trying. I've searched Google and the forums, but can't really find an answer.

Any hints would be most appreciated.

Thanks to you all,
Vito
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Last edited by Vito DeFilippo; July 27th, 2006 at 12:28 AM.
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Old July 27th, 2006, 12:15 AM   #2
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Quote:
Originally Posted by Vito DeFilippo
...The manual suggests setting the mic level on the transmitter so that the peak metre on the receiver barely lights up...
I don't think I've used Telex, but typically you'll set mic level on the transmitter so that the peak indicator on the *transmitter* barely lights up.

If you've eliminated other stages in which gain could be overloading (and it sounds like you have) that would point to overload at the transmitter preamp, which is very common.
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Old July 27th, 2006, 12:36 AM   #3
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Hi Seth,

Yeah, this system has no peak indicator on the transmitter, just on the receiver. As I said, when I set the mic output high enough to make it barely light up, it seems hot, so I had lowered it. Perhaps it needs to be lowered even more as you suggest, darned if I know...

Could it be the XLR cable? Does that make any difference (in the sense of quality of the cable).

Thanks for your input, much appreciated.
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Old July 27th, 2006, 07:37 AM   #4
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Quote:
Originally Posted by Vito DeFilippo
Hi Seth,

Yeah, this system has no peak indicator on the transmitter, just on the receiver. As I said, when I set the mic output high enough to make it barely light up, it seems hot, so I had lowered it. Perhaps it needs to be lowered even more as you suggest, darned if I know...

Could it be the XLR cable? Does that make any difference (in the sense of quality of the cable).

Thanks for your input, much appreciated.
I'm looking at the info on the Telex site about the ENG100 and I don't see anything about any peak indicator on the receiver - it does say there are a couple of diversity indicators, I presume they light to show which antenna is in use at the moment, but nothing about any level indicators.

If the output of the receiver is too hot, it can overload the camera's audio inputs even if the cameras meters don't indicate an overload - the meters are after the preamps in the signal path. Try this - turn the receiver's mic output trim all the way down, set the camera to manual, set the camera's audio recording level controls to about 2/3 of the way up and gradually turn the receiver's output control up until the camera meter reads normal recording levels.
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Old July 27th, 2006, 07:43 AM   #5
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The first thing to try is to plug headphones into the monitoring jack on the receiver (assuming it has one) to see if the sound coming from the receiver is pure. If it is then the problem is with the camera. If not then look for distortions coming from the wireless system. Possibilities are 1) Multipath - the fix here is simply to move the transmitter and receiver a little 2) Interference - try another channel 3) weak batteries on transmitter and/or receiver - replace 4) phantom power on when it shouldn't be - turn off 5) mic being used too hot for the transmitter - select a mic with lower output or pad existing mic 6) transmitter or receiver defective
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Old July 27th, 2006, 08:53 PM   #6
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Thanks so much for taking the time to answer and for your suggestions. I'll try them all out and see what I find!

Ciao,
Vito
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