Static and Cutting out

Bbillups

Member
So, we are doing Into the Woods at my high school and I'm running the wireless microphones. we are using a mix Sennheiser ew 300 receiver an packs and Sennheiser ew 100 g3 receivers and packs. I am running ten packs( both kinds) from a Mackie sound mixer into a Mix wizard which in turn runs to a eurodesk which goes out to our speakers. It appears that only the receivers from the Mackie are cutting out and one pack (which just so happened to belong to main actor) is creating a lot of static and a little feedback. Is there any way I mix this out or anything I could try with the pack. I've already checked the squelch and the frequencies and signals are all okay. I can't change the orientation of the boards or packs. Please this is my first real musical and I don't really know what I'm doing...
 
Tell us more about your set-up and what you're hearing. Would you describe the static as popping or a constant rushing sound?


- Do your receivers have line-of-sight to the playing-space of the stage?
- Are your frequencies truly clean, have you done a full coordination?
- The G3 have a sensitivity setting, is it set the same for all transmitters?
- Are all the lavalier mics brand new? Have they been tested?
- Are the lav connectors screwed down onto the transmitter?
- Are the output power of the transmitter identical?
- Where does the actor hide the transmitter? Does his antenna touch bare sweaty skin?
- Are all the output levels of the receivers the same level?
- Are the gain setting's of all three consoles set so that nothing clips?
 
A good resource for finding clear frequencies is sennheiser's frequency finder. Find Available Frequencies
Even if you are on frequencies that are clear of outside noise you might be having intermodulation problems between the mics. Senhiser also has a tool for calculating intermod free frequencies called SIFM.

Your problem realy seems like rf dropouts or interference. How are the antennas for your receivers set up? The feedback would mean your levels are too high, and the mics are picking up there own sound from the speakers.
 
-the recievers have a direct line of sight
-we checked every frequencies and nothing is overlapping
-the sensitivity is the same for every pack
-everything's been tested weeks before this and every night before rehearsal
- my A2s have doubled checked everything
-all the power is the same
-the packs are underneathetheir clothes and have sheaths and mic belts on them
-all the outputs have the same levels
- and gain has been set so nothing clios

the mics and packs seem to work when we test them by themselves on the stage but the static and cutting out happens only when the actors physically go on stage in full costume. could the multiple layers of clothing be disrupting the signal? is there anyway to boost the signal, either through packs or receivers or with different antennas. we have to use an antenna splitter and two radio shack antennas because the rack mount of the receivers on the mackie doesn't allow much space
 
Can you list your frequencies? I know this sounds like a lot of work, but some transmitters may be too close to each other. Also, a picture of your set-up would be nice, too.

Even though the sensitivity is the same on each pack, this doesn't guarantee it is set correctly. Start with the sensitivity all of the way down on each pack and slowly bring it up while talking into it at the level it will be used. Watch the RF monitor on the individual receivers and stop before it goes into the yellow section. You can now set the gain on the mixer by doing the same thing.

I don't think the multiple layers of clothing are disrupting the signal (if that were the case, lav's would be near useless). I'm going to guess the Radio Shack antennas are your issue. Bring the mics close to the receiver (but not too close that you overload it) and have them walk away from you towards the stage while talking. If you find a point where the mics start cutting out then you found your maximum operating radius. Try these suggestions and let us know what you find.
 
When you say the mics work when on the stage alone do you mean one mic at a time?

If this is the case it would seem like when there are more mics on the stage together they are inter-modulating with each other creating interference. Even though each mic is tuned to a different frequency they still may be interfering with each other. This can happen for multiple reasons. One because the frequencies are too close together. Or because when mics are close together physically they can create interference with each other(the closer they are the worse it can get). The SIFM software can help calculate frequencies that are intermod free.
 
I realize that the show is over now, but for future reference it is worth examining the mics themselves because when I read the OP, I immediately thought "mic wire failure". We have had 12 G1 and recently upgraded to G3 and over the years have discovered that the mics tend to fail at the point where the wire joins the beltpack connector. They seem to work when we test them but as soon as the actor starts moving you get drop outs and static as the wires move and connect and disconnect. It's not abuse, but a fact of life... the wires are very thin and as the actor moves the wire cannot help but move as well, the connector however holds the wire in place and over time, it breaks. To test, try jiggling the mic wire about 4" above the connection. If it has failed it will create an AF signal at the receiver... as the connection is made and broken and made and broken.

The solution is to cut the wire an inch or so above the connector and resolder it to the connector. Replacement connectors can be expensive but I discovered that if you cut the plastic connector cover away, what remains is a fairly robust connector and we use shrink wrap to replace the plastic cover. We have also learned to make sure we always have spare mics because we never know when they are going to fail...
 
Yes, the dreaded broken wire at the connector strain relief. The main cause of that is people taking the mic cord and wrapping it around the beltpack for storage. It kinks the cable in the same location every time and eventually it breaks. I try to remind the users of beltpack mics to not wrap the cable in any way before they turn it in to me and it avoids damage.
 
Correct about the wrapping the mic around the beltpack. That was something we learned when we first got our first system... Wrapping the mic cable around the beltpack is fast, easy and keeps the cable neat... but also tends to damage the mic wire..
We store our mics and beltpacks separately and coil the mics...
 

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