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Old April 13th, 2009, 07:54 AM   #1
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mechanical pops from wireless lav system

I'm getting a mechanical pop from my wireless lav system.

It does not seem to be related to movement on the speaker's part although movement does exacerbate it. My buddy and I have identical setups except we are running different frequency ranges (he's using the "B" range and I'm using the "A" range). We think it is only occuring on my system and not his, but, I haven't been able to record much with his yet due to shoot scheduling.

For now I will do our next single-speaker shoot with his system instead of mine and monitor for this problem. I will also see if I can get customer support to listen to this attachment.

Does anybody here have any ideas? Attached file is 1 second / 172KB size.

System is Sennheiser Evolution G2 100 Series - Camera Mountable UHF Lavalier Wireless System with EK100G2 Receiver SK100G2 BodyPack Transmitter and ME4 Microphone (A 518-554MHz).
Attached Files
File Type: wav lavAudioTiny.wav (172.5 KB, 223 views)
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Old April 13th, 2009, 08:44 AM   #2
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Quote:
Originally Posted by Dave Speer View Post
I'm getting a mechanical pop from my wireless lav system.

It does not seem to be related to movement on the speaker's part although movement does exacerbate it. My buddy and I have identical setups except we are running different frequency ranges (he's using the "B" range and I'm using the "A" range). We think it is only occuring on my system and not his, but, I haven't been able to record much with his yet due to shoot scheduling.

For now I will do our next single-speaker shoot with his system instead of mine and monitor for this problem. I will also see if I can get customer support to listen to this attachment.

Does anybody here have any ideas? Attached file is 1 second / 172KB size.

System is Sennheiser Evolution G2 100 Series - Camera Mountable UHF Lavalier Wireless System with EK100G2 Receiver SK100G2 BodyPack Transmitter and ME4 Microphone (A 518-554MHz).
Sounds like a pretty typical wireless "hit" and it's probably not indicative of any fault in the equipment. Try choosing a different frequency in the block and be mindful of antenna orientation. Make sure the transmitting and receiving antenna are parallel to each other and are clear of nearby cables and metallic objects. Does the cable from the mic cross over the transmitter antenna? If so, try leading it around the other side of the talent's body. While you're at it, experiment with where you've clipped the transmitter to the talent.

Are there other wireless units in operation at the location? Strong transmitters on a nearby frequency? Try scanning with the transmiter turned off to see if the receiver locks onto some other transmitter on the same or a nearby frequency.
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Old April 13th, 2009, 11:19 AM   #3
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That is a classic Hit sound, cause is RF interference due to a cell phone, CB radio, TV station, antenna placement, ionosphere etc... Change frequencies or run a XLR mic cord as a backup.
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Old April 13th, 2009, 12:46 PM   #4
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Yep, Mark is right. Should have mentioned cell phones and Blackberrys on the set as a frequent cause of this sort of hit. Make sure all such devices are completely OFF, not just set to silent. When powered on they "phone home" every few minutes to let the system know what cell they're in and this can interfere wth wireless.
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Old April 13th, 2009, 01:10 PM   #5
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How close is the Receiver to the Transmitter?
Can they "see" each other? Line of sight, is the antenna covered or open air?
Is the antenna oriented horizontally or vertically?
Is the antenna bent or straight?
What is the Squelch set to?
Was an "Autoscan" performed?

If some of this doesn't make sense, I invited the local Sennheiser rep into our studio to give a little run down that might help Super high quality Wireless microphone set-up for church, school, corporate, or live event on Vimeo
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Old April 13th, 2009, 01:48 PM   #6
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OK guys thanks for all these initial responses.

I am having the guys wear the transmitter on their belts (antenna vertical), the receiver is mounted on the hot shoe of my camera (antenna horizontal), so the antennas are *not* parallel. If I understand that correctly.

The distance is anywhere from 10 feet to 60 feet is about tops.

Transmitter antenna is bent, pretty far from straight but not kinked over anywhere, it came a little bent and has become more bent due to talent wearing the transmitter in a jacket pocket. I've stopped this, but, the antenna was straigher even back when I first noticed the noise.


Squelch on receiver is 0.

Mic cable may very well cross antenna, I'll look for that as well.

We are sometimes running another G2 in very close proximity, but I have heard these hits as you describe when we are only running one system. The only audio we are running is these one or two wirelesss, and we are shooting with two xh-a1.

We are shooting outdoors (fishing) in a number of environments. Some more urban, some more rural. There doesn't seem to be a good correlation between the environment and the sound. I hear these hits while monitoring but haven't known what to do.

I have told the receiver to scan (transmitter off) and it says "4 channels free" or something and I say "ok" and then turn the transmitter back on and tune it to whatever the receiver is showing. I don't really understand what the banks are for, it looks like I need to go back to the manual to re-read some of that. If I recall the information was precise but a little short on example and/or "the why" of things.

Cell phones are either all the way off or on airplane mode... there's also at least one blackberry in the mix-- according to the owner it's a non-issue due to the type of signal they transmit. I don't know and don't care as long as I can get these hits to stop.

Doesn't everybody in the free world mount their reciever to the hot shoe? Or what is a good alternative? Velcro to the tripod?
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Old April 13th, 2009, 02:23 PM   #7
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Flip the Transmitter's clip and point the antenna down. This helps keep the antenna straight.
Sennheiser Wireless G2 hot shoe set-up on Vimeo

Banks are easy to understand. They are simply a "Group of channels."

You can Autoscan a Bank (Group of channels).

If Sennheiser engineers didn't arrange the 1440 frequencies into these small groups (Banks), when you hit Autoscan you would be waiting for a very long time.

If a certain "Group of channels" is giving you fits, simply switch to another Bank.
There are 8 Banks on the G2 series and 1 user definable.

When setting up in a "foreign" area. It's worthwhile to consult the Sennheiser frequency finder Find Available Frequencies

The Squelch should be set to "High" if you're within a few feet or getting hits (interference). "Low" is the normal setting for maximum range.

See 5:38 of this video Sennheiser Evolution G2 wireless Tutorial at DVcreators.net

You can mount this Receiver Vertical using either a Bracket1 or try a search on Markertek.com for a Micmate.

Hope this helps,
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