Loud Pop on Sennheiser Wireless Mic

[Richard Crowley]

My first thought was that it may be static electricity discharge. Does the pastor wear a clerical gown (or other garb) that might be static inducing? Or a silk tie, etc? I don’t think that it sounds like a result of RF “hits” from interference, but that is just a guess.

When the pop happens, does the microphone audio come back instantly, or does it take a fraction of a second to return after the pop? What do you see in the RF and audio displays on the receiver?

There are several experiments you can do to make a differential diagnosis of the situation (as they say in the medical biz.) You can pick the same hour on some other day (Saturday, Monday, etc.) and just leave the transmitter sitting on the lecturn or wherever the pastor normally stands. See if it makes the same noises. Or have someone else wear it for a few hours (perhaps office staff or janitor, etc.

Do you get the same pops from the receiver when the transmitter is turned off?

[Steve Jackson]

Thanks for the response.

He is pretty laid back so there is no gown involved. Usually just normal casual attire.

I believe audio comes back pretty much immediatelly. I have tried to watch the receiver but I haven’t had my eye on it when the pop occurs.

This is a new church in a temporary space. So we setup and teardown each Sunday. So the entire setup isn’t very accessible for testing on off hours.

I like the idea of having the mic set in the general area and see if anything is generated. I’ll try to do that while we setup this Sunday.

I’ll also try to test with the mic off. Much of the time, that channel is muted except when the pastor is talking so I don’t know if it occurs at other times or not.

The idea of static discharge does seem plausible because it is a single pop with no noticeable interference otherwise. On the negative side, this mic has been in use since Nov ’09 in this space and another space and connected to a variety of boards/power amps with no problem. In July, we implemented a new sound system with a Mackie board at another space. I don’t recall the problem at that space but I’m not sure. In August, we returned to the current space. The problem has been pretty regular for the past 3 weeks.

So we have full disclosure, the recievers are rack-mounted in a portable case along with a power conditioner and a 2 channel EQ. Connections to the Mackie are by 10-12’XLR. Distance from the mic to the reciever is maybe 50′ at most.

We do have 2 recievers/mic setups but only 1 is used right now so I may run the pastor on the 2nd setup this week to see if any pops are generated and also bench test the 1st during setup to see what happens.

Since my testing time is so limited, I really appreciate your input so I can maximize my efforts in the right areas. I’ll see what I can come up with this week.

Thanks.

[Brian Reynolds]

If it was electrical, a few things that crossed my mind, a regular but random splat is commonly caused by motors like on fridges, washing machines or small air conditioners. Are you on the same circuit as any items like this? Motors also emit quite a lot of RF when it turns on, so even being on a different circuit but having the radio mic receivers within a few metres may pick it up (walls DON’T stop RF interference). And does it show up on ANYTHING else like video monitors or TVs?

If it was an acoustic pop could it be a blast of air coming from the “talents” nose? (normally occurs on males of large stature that take LARGE and frequent breaths), I know it sounds strange but often broadcast TV studios use inverted OMNI lapel mics to solve the problem.

Changing the radio mic frequency will not solve either of these 2 problems.

The difference between Knowledge and Wisdom is… Knowledge is the knowing of facts…. Wisdom is the sensible application of good quality knowledge…

[Ty Ford]

Hello Steve and welcome to the Cow Audio Forum.

Try positioning the mic so it is facing down instead of toward his face and see what happens.

Regards,

Ty Foed

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[Steve Jackson]

Not real sure about what else is on the circuit but based on location, I don’t think there is much on it. That assumption depends on how logical the original electrician was. We don’t see any other evidence of electrical RF interference on other devices.

I was able to test the mic just sitting on a table for a while before service with no problems. That kind of tells me that it may not be building electrical which I take as good news because we probably couldn’t do much about fixing it.

I am beginning to suspect the mic on the transmitter. Do they often fail this quickly (approx 9-10 months)?

I may try to put him on the 2nd mic to see what happens next week.

Thanks

[Charlie Vansant]

Steve – Did you ever figure out what was happening with your mic? We are experience the same issue.

Thanks!

[Steve Jackson]

Sorry I hadn’t responded in a while. I did get the original problem resolved. I noticed as we ran off of a second mic/reciever pair that there would be significant noise on the channel connected to the 1st receiver with the transmitter off. Watching the RF display on the reciever, I was seeing significant spikes. All of this is with the transmitter off. So I changed the frequency for that mic/receiver pair and the pop stopped occurring. My assumption is that with the transmitter on, the RF noise at a low level would be overridden by the signal from the transmitter. But the spikes in RF noise would overpower the signal from the transmitter and manifest as a pop.

Interestingly, we have been going along for a while with no problems. But just this past Sunday, we had a few episodes of noise, not really pops. I’m not sure if it was a cell phone causing interfence or something else. It wasn’t the normal cell phone burst that I have heard on other systems. I may encourage the pastor to either remove or shut off his cell phone to see if it reoccurs.

Thanks

[Ty Ford]

Steve, et al,

I have personally had wireless ranges go from 50 feet to 1 foot due to blackberry type cellphones. Not just the tweedle, tweedle tweedle, but totally blown out.

Putting them on standby usually doesn’t work. They have to be off, period.

Regards,

Ty Ford

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[Ryan Lancaster]

Hey guys,

I’m having the SAME problem with my seinheiser g3 transmitters and receivers. The teacher occasionally has a very large pop for no reason and then audio resumes immediately. I know its not wireless signal interference from other devices, and I know its not because I’m not on an open frequency. I don’t quite understand the original solution so I’m trying to get a clearer understanding of how to remedy this issue.

Anything helps!

Ryan

[Ty Ford]

Guys,

Are the receivers directly attached to a camera in all cases? Which camera? Phantom power is off, right?

Thanks,

Ty Ford
Cow Audio Forum Leader

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