Sennheiser G2/G3 interference question

O

osoc13

New member
I'm having an impossible time getting clean audio with my Sennheiser wireless kits. I have an A block G2 and a B block G3. I scan for frequencies before every shoot, keep a direct line (as best as I can) between the receiver and transmitter, and rarely have the receiver and transmitter farther than maybe 20 feet apart. I have the cell phones off from anyone who is mic'd. Yet probably 50% of the time I'll get really terrible interference intermittently.

I guess I'm wondering what troubleshooting I should do or if there are any additional steps I should take prior to recording to avoid this issue. I've scanned the forum and believe myself to be somewhat competent, but I guess not.

Thanks!
 
I'm running 2 block As, and 1 block B, and only once have I gotten RF hits and that was on the block B (in downtown Atlanta). There are a couple of things to check:

Make sure the transmitter antenna is not taped or in any way bound to the actor's body. For some reason, if the transmitter antenna is held firm to the talent's body, the range is greatly decreased.

Try to keep your recievers a few inches away from your other electronics in your bag. I clip my recievers onto the outside of the bag, making sure the antennas are free and clear from entanglement with other cables or each other.

Are you getting interference on both blocks?
 
It's not enough to only have the cell phones of the people who are mic'ed. All cell phones and PDAs within about 100 yards of the set need to be completely powered off.
 
gpforet said:
Make sure the transmitter antenna is not taped or in any way bound to the actor's body. For some reason, if the transmitter antenna is held firm to the talent's body, the range is greatly decreased.
Click to expand...

If the antenna touches the skin you have about 70dB of attenuation - if the antenna is just 1cm away from the skin you get most of this back.



gpforet said:
Try to keep your recievers a few inches away from your other electronics in your bag. I clip my recievers onto the outside of the bag, making sure the antennas are free and clear from entanglement with other cables or each other.
Click to expand...

If you are using more than one receiver, keep them apart as back-emf can transmit from one receiver to the other and cause interference.



Steve House said:
It's not enough to only have the cell phones of the people who are mic'ed. All cell phones and PDAs within about 100 yards of the set need to be completely powered off.
Click to expand...

Yes - cell phones MUST be fully OFF and not on silent as they can cause interference when in silent mode.
 
I knew it was a gain hit, I had no idea it was THAT MUCH!

John Willett said:
If the antenna touches the skin you have about 70dB of attenuation - if the antenna is just 1cm away from the skin you get most of this back.





If you are using more than one receiver, keep them apart as back-emf can transmit from one receiver to the other and cause interference.





Yes - cell phones MUST be fully OFF and not on silent as they can cause interference when in silent mode.
Click to expand...
 
Thanks so much for all the helpful suggestions! For a lot of my work I don't have the luxury of making sure every cell phone within 100 yards is turned off unfortunately, but all these other tips are going to come in handy I'm sure.
 
osoc13 said:
Thanks so much for all the helpful suggestions! For a lot of my work I don't have the luxury of making sure every cell phone within 100 yards is turned off unfortunately, but all these other tips are going to come in handy I'm sure.
Click to expand...
If you don't have that "luxury" then resign yourself to carefully monitoring each take in their entirity and be prepared to shoot the same scene over and over again until you get enough takes with enough clean audio that you can chop 'em up and assemble a complete scene free of RF hits.
 
osoc13 said:
Thanks so much for all the helpful suggestions! For a lot of my work I don't have the luxury of making sure every cell phone within 100 yards is turned off unfortunately.
Click to expand...

But you should be able to make sure that the cell phone of everyone working on the production is turned off (NB: OFF - not silent).

If it's a live performance, an announcement should be made to turn mobiles off - and include an explanation as to why they should be off and not silent (IE: even on silent the cell phone regularly announces itself to the nearest cell, and if that is far away a cell phone can transmit up to 2 or 3 Watts of power - compared to a radiomic. with a maximum of only 50 thousandths of a Watt).
 
Ok, I was wondering if I was alone on this. But seems like i'm not.

I have the same issue (terrible interferences on a Sennheiser G2 block A). I use a sony in the 700mhz range and works fine. An AKG in the same range, and all fine.
Actually, what is so strange is that I used the same G2 kit for 2 years, and worked flawlessly (can't remember a single interference in those 2 years). Now it seems like I simply can't use them anymore.
I know what you are thinking: They are broken, have an antenna broken, etc... But I sent them to a sennheiser dealer here in Costa Rica, to get fixed them, and they couldn't find anything wrong (even using the same mic attached that I use).
I tried the mic in another G3 someone lend me, and the mic works fine (a Countryman B6). Even bought another mic (Oscar ST) and the interference is there.

It actually works fine for like 10-15min, sometimes, and then it all gets unusable. But I tried them here at my house for 3-4 hours, and works fine. Is more like when they detect that is a serious recording, then they refuse to work

Any suggestions?

I'm even thinking about buying another set, maybe in a different block, so I can keep using my mics. You think is the best option?
 
Not sure about Costa Rica but the 700mhz band has been illegal here for over a year, and the band is beginning to fill rapidly with licensed operators so interference will grow.

A quick google search shows Costa Rica is also affected by the 700mhz band reallocation.

However, Sennheiser block A is in the 500mhz band so should not be impacted. Something else must be going on.

My G3 block A gear has performed flawlessly. The fact that they worked fine but suddenly began failing implies that something has changed.


Harlockr said:
Ok, I was wondering if I was alone on this. But seems like i'm not.

I have the same issue (terrible interferences on a Sennheiser G2 block A). I use a sony in the 700mhz range and works fine. An AKG in the same range, and all fine.
Actually, what is so strange is that I used the same G2 kit for 2 years, and worked flawlessly (can't remember a single interference in those 2 years). Now it seems like I simply can't use them anymore.
I know what you are thinking: They are broken, have an antenna broken, etc... But I sent them to a sennheiser dealer here in Costa Rica, to get fixed them, and they couldn't find anything wrong (even using the same mic attached that I use).
I tried the mic in another G3 someone lend me, and the mic works fine (a Countryman B6). Even bought another mic (Oscar ST) and the interference is there.

It actually works fine for like 10-15min, sometimes, and then it all gets unusable. But I tried them here at my house for 3-4 hours, and works fine. Is more like when they detect that is a serious recording, then they refuse to work

Any suggestions?

I'm even thinking about buying another set, maybe in a different block, so I can keep using my mics. You think is the best option?
Click to expand...
 
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