Interference type issue with Sennheiser G3 kit

[Ty Ford]

Hello Joe and welcome to the Cow Audio Forum.

Sorry for your pain.

Sounds like an RF problem. What shape are your transmitting and receiving antennae? Are their connections to the transmitter and receivers solid? If one or the other of them has pulled off the circuit board inside, it could do this.

Can you operate them without this problem in other locations with the same sort of conditions. In pocket, etc.?

Were both wireless mics doing this?

Where were the receivers?

Regards,

Ty Ford
Cow Audio Forum Leader

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[Joe Bressler]

Hi Ty,

All antennae were straight and the receivers were both mounted on the camera rig.

I had another shoot where I used the sennheisers with the same problem. I had tested them before that shoot and had also tested them again before this shoot, but not in similar conditions. They worked fine in stationary, no-stress tests. However after this shoot I tried to test them again walking around outside with the receiver in pocket by myself, trying to get the issue to present itself, but I don’t really think it’s the same.

BOTH mic’s were doing this.

Thanks for your quick response!

-Joe

[Peter Groom]

HI – to my ear there were 2 different issues.
The 1st problem in the start of the clip sounds more like a physical issue. So the mic cable, or the mic plug, or the socket, or a dry solder joint etc etc. It seems related to movement / paces.

Then I hear RF interference issues on the laster part which i agree with Ty on.

How come you didnt hear it as soon as it occurred and then address / adjust / fix before proceeding.
You were wearing headphones I presume?

In a city like NY you really have to be presuming that there WILL be issues around the corner so listening and adjusting constantly.
Peter

Post Production Dubbing Mixer

[Joe Bressler]

Hi Peter,

Thanks for your response. What could be done to reduce RF interference besides doing the channel scan and using the bank with the most free channels? We hadn’t changed locations since the initial scan.

Understand nyc would be prone to rf interference but the exact same issue has presented itself outside of the city. Would changing the squelch help?

Thanks
-Joe

[Ty Ford]

Joe,

Yes the antennae may be straight, but are they still soldered to the circuit board inside the transmitter and receiver?

Is there anything else on your camera rig when this happens?

Like an external monitor or monitor/recorder?

Regards,

Ty Ford
Cow Audio Forum leader

Want better production audio?: Ty Ford’s Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford’s Blog

[Peter Groom]

Hi
Im far from an expert when it comes to radio interference, but I can tell you that the best solution is to wear headphones.
If Im directing, and i see the sound man take his cans off, I stop and ask him why. Its crucial that people listen continuoulsly, just like the camera man watches throught.

In the UK only 1 bank is allowed by law. I cant speak for anywhere else but were you definitely working within the correct frequency set for your territory.
were all mobile phones turned off anywhere near?

Peter

Post Production Dubbing Mixer

[Joe Bressler]

Hey all,

Thanks so much for your continuous advice on this. The rig was an a7s with XLR adaptor plugged into the shoe, with the two recievers mounted by Velcro on a movcam cage. I was monitoring sound, and stopped to fiddle with the system upon hearing the issue, but it was quite intermittent and like I said I don’t know what adjustments to make besides finding a clear channel.

The talent was holding a radio and had his cell phone on. This sounds like hell for a radio mic system so I would imagine that wasn’t helping.

The transmitter and receiver that I had been using were pretty much brand new units. Used only once before, with the same issue. So I doubt that the antennae had become un-soldered. Additionally oddly enough the rental transmitter was causing the most problems and was switched from the main talent to his buddy who was also mic’ed but was not speaking much.

How can I find out what frequency I should be operating within in my region?

Thanks again
-Joe

[Peter Groom]

In the Uk it would be who you pay for your permission to use a radio mic. Theyre all licensed.
peter

Post Production Dubbing Mixer

[John Fishback]

Try this link to Sennheiser’s Frequency Finder. It may help. As stated earlier, NYC is awash in rf traffic.

[Tom Salyer]

I work with four sets of Senn G3 wireless and your type of zzzzt zzzzt RF interference happens to me from time to time even though I’ve scanned and set up on a clear frequency block.

Once I check to see the antennas are not against bare sweaty skin and I check all cable connections, I seem to fix it by simply opening up the receiver and choosing another clear scanned block.

It’s awkward after wiring somebody up and listening to a clear signal, to have the subject walk 30 feet way and the zzzzt start … but I’d rather go right back to them and quickly hop up a frequency block or two than convince my producer ghosts messed up his tracks.