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Sennheiser G3 wireless lapel unpredictable noise.

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Alex Sibbison
Sennheiser G3 wireless lapel unpredictable noise.
on Jan 28, 2015 at 9:49:47 am

Here is a link to a common example of the noise issue I am getting from both of my Sennheiser EW100 G3 wireless lapel kits. Even doing a new frequency scan at each new location and changing frequences doesn't always get rid of the issue. It seems to happen randomly.

https://www.dropbox.com/s/j00l561ruwx7vdw/Sennheiser%20G3%20common%20mic%20...

This example I have the receiver plugged into my Sony FS100 video camera and transmitter and mic on the front of the karate teachers uniform. This is the second kit I have purchased and I am experiencing the same problem. My other thought is that it may be the camera?

Any help would be very much appreciated.
Thanks,
Alex


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Steve Kownacki
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Jan 28, 2015 at 1:33:25 pm

Except for the pop at :27, sounds like cell phone interference to me.

Steve





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Richard Crowley
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Jan 28, 2015 at 5:23:29 pm
Last Edited By Richard Crowley on Jan 28, 2015 at 5:33:58 pm

Sounds like RF propagation/interference problems to me. The receiver is operating at the bottom limit of what it can extract from the transmitted signal. When it dips below the threshold, you get that characteristic noise.

You did not mention what frequency band you are using (or where you are)? There are certain locations and frequency bands that are notorious "RF Hell" Does the kit exhibit the same symtoms in a different location? At a different time? At a closer distance?

Assuming you have the antennas deployed properly (transmitter antenna is not folded over or against the skin, etc. Are you using the minimum distance you can get away with? Wireless mics are not magic. They are subject to the same (or even) worse interference as anything else.

That does NOT sound like cell phone noise to me. If you have ever heard it, there is no mistaking the Brrrrrr--Brrrrrrr--Brrrrrrr distinct digital noise.


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Alex Sibbison
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Feb 4, 2015 at 6:43:49 am
Last Edited By Alex Sibbison on Feb 4, 2015 at 6:47:03 am

Thanks everyone so much for your responses.

I'm in Melbourne, Australia. Frequency band B = 626-668 MHz

For example today I was filming in the city in an office space and I got everyone to turn their mobile phones off. I'm not sure it helped as the sound was still there on occasions as the talent moved around.

This is an example from today before the shoot https://www.dropbox.com/s/gq58yuvbyq9q7tf/RF%20Noise%20example%202.mp4?dl=0

The aerials are in good positions. Out in the suburbs the interference is less frequent/intense.

I think I need to buy a new kit on a different frequency band. I'm sure this equipment should be more reliable.

Let me know if you have any other ideas.
Thanks


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Richard Crowley
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Feb 9, 2015 at 7:31:18 pm
Last Edited By Richard Crowley on Feb 9, 2015 at 7:33:58 pm

Your sample file URL doesn't work.

Noise that happens as the transmitters move around is not caused by cell phones or interference. It is a simple RF propagation problem.

You never mentioned what kind of working distance you are trying to use, so we are unable to evaluate that major factor.

It seems possible that the transmitter or receiver have drifted so they are not properly tuned to each other. Or an antenna may actually be broken insternally even though it looks OK on the outside.


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Alex Sibbison
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Feb 10, 2015 at 12:08:31 am

Working distance is usually around 3 or 4 meters away, usually an interview setup or close demonstration in front of camera.

I have updated the link here
https://www.dropbox.com/sh/5gtcoovdygdcd9v/AADbOGco2sVv8VnW0lkdDzw3a?dl=0

There is recent outdoors clip where I recorded 3 interviews that went for around 10 minutes each then in one interview I got a random burst of RF interference. I assume there is nothing more I can do to prevent this? As naturally wireless has it's problems?

Thanks for your support.


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Richard Crowley
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Feb 10, 2015 at 12:38:36 pm
Last Edited By Richard Crowley on Feb 10, 2015 at 12:41:12 pm

It sounds to me like your kit is simply broken. An antenna connection is broken internally (severely limiting the amount of RF transmitted or received). Or either the transmitter or the receiver frequency or RF tuning circuits are no longer aligned to properly communicate with each other. Or several other things that could be wrong.

Of course, we are assuming that you are performing the tests with NEW, and KNOWN GOOD batteries. Not batteries you bought from some place that have been sitting on a dusty shelf for a year. NOT RECHARGEABLE batteries of any kind!!! Good, name-brand primary cells. A rechargeable battery, even when FULLY CHARGED only has the terminal voltage of a nearly-flat primary cell. Whether we like it or not. Most wireless kits perform terribly with rechargeable batteries.

The symptoms are those of simply "signal starvation" where the receiver is not getting enough signal from the transmitter to support a good, noise-free connection. This could be a problem with the transmitter. Or it could be a problem with the receiver (or even both). With only a single kit at hand, you have very limited options for troubleshooting.


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Alex Sibbison
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Feb 10, 2015 at 10:48:19 pm

This is great information thank you.

I often use cheap batteries (and have used rechargable in the past and same problem) because I thought it only effected the duration of charge, but if it effects the performance I will try it with good name brand batteries next.

I have 2 kits, one I currently put in for service at the Sennheiser certified repair shop. The interesting thing is that I have borrowed friends sennheiser kit (identical model) and had the same issue. Fingers crossed it's just a battery type issue.

I also borrowed the new sony uwp-d wireless lapel system and only used that out in the suburbs but that seemed fine on the one occasion I used it.
If all else fails I'll switch to the Sony digital/analogue system but I will try high quality batteries first with the Sennheisers.


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Thomas Barnes
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Dec 12, 2016 at 9:21:08 pm

Hey Alex,

I'm in Melbourne also - and have been experiencing similar problems, with the exact same wireless lav. Did you come up with a solution?

Cheers, Thomas


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Alex Sibbison
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Dec 12, 2016 at 11:21:18 pm

Hi Thomas,

Yes, the solution is sell and don't use Sennheiser G3s and buy Sony UWP-D kits.


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Eric Toline
Re: Sennheiser G3 wireless lapel unpredictable noise.
on Feb 4, 2015 at 1:15:03 am

I don't know where your tx & rx level settings are but you should set them both at -18 to start with and adjust from there. Your camera audio levels should average about -10 as a good mid level point between -20 & "0" all dbfs.

"I push the RECORD button and hope for the best"


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