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PROBLEM SOLVED - new thin cable DPA 4063 has RF problems


RadoStefanov
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"You mentioned the cellphone's rfi, Jeff. This will occur only when the mic is on a zx. This same phone will not cause rfi when the same mic is on a cable. Is that not a curios fact, worth inquiring about?"

 

I have had cell phone interference on hard wired lava before. Even if this issue has not been discussed in adequate detail to answer ALL of tour questions, one thing is abundantly clear which is RFI type problems are quite unpredictable and subject to all sorts of conditions which are not always easily defined or described. A given microphone in a certain situation MAY have a problem and in what appears to be an identical situation, exhibits clean performance.

 

As for explaining why this is so, I am not qualified to explain this (but there are several others here who could explain all these things if willing to take the time to answer your specific questions).

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" I don't know why you don't want me ask this question? "

you are incorrect in that conclusion, I suspect JW is saying about what I say: it has been discussed thoroughly already.

" Why are microhones more susceptible to rfi when used with a plug-on tx, but less so when cabled? "

that can be difficult to say, as there could be numerous and various reasons, -but one is certainly: proximity-

as well as the fact that your "more susceptible" observation may be flawed.

There is plenty of Physics out there for all sorts of issues!

The observation is just that. What may be flawed is the conclusion drawn from it and of course, that's very possible. Which is why I was asking for others to share their experiences.

Proximity however is an unlikely culprit, as that was the same for both modes of transmission.

I know you don't like this, but would you mind kindly pointing me to where this issue has been thouroughly discussed? And don't say this thread...

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"You mentioned the cellphone's rfi, Jeff. This will occur only when the mic is on a zx. This same phone will not cause rfi when the same mic is on a cable. Is that not a curios fact, worth inquiring about?"

I have had cell phone interference on hard wired lava before. Even if this issue has not been discussed in adequate detail to answer ALL of tour questions, one thing is abundantly clear which is RFI type problems are quite unpredictable and subject to all sorts of conditions which are not always easily defined or described. A given microphone in a certain situation MAY have a problem and in what appears to be an identical situation, exhibits clean performance.

As for explaining why this is so, I am not qualified to explain this (but there are several others here who could explain all these things if willing to take the time to answer your specific questions).

(Sorry, I don't know how to multi-quote in Tapatalk)

Of course, I don't expect anyone to explain this to me, especially since I seem to be the only one curious about this. And maybe it is a non-issue. And you are certainly right about the unpredictability of rfi.

And yes, I've had rfi on hard-wired mics, too. I'm not saying that they are impervious, I was just trying to find out if there is a trend for more rfi in the audio on wireless transmissions. Anyway, at the moment it seems like there is not much interest in this, so we can leave it at that, I suppose.

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I sat down for 5 minutes today to document this issue, so I'm pretty sure they will have no problem replicating this once they have the Zaxcom gear on hand to test.

 

Stereo sample of the older 4063 [L] and the newer 4063 [R]

 

It's been 10 days since DPA's last update and my fingers are crossed that they can come up with a simple solution in a timely manner.

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Why do these RF problems keep coming up with Zaxcom? Same for the TRX 742. I think Zaxcom needs to start addressing this problem.

Hey, Geoff, I don't think you've been following this whole issue carefully. Quite awhile ago when it is was discovered that several of the mics we typically use were overly sensitive to RFI when used with digital wireless (and Zaxcom was and still is the main supplier of pure digital wireless for our sort of jobs), Zaxcom DID address the problem by working with the manufacturers to IMPROVE their RFI rejection --- this was a win-win situation for everyone --- we found ourselves now with an improved Sanken COS-11 and Schoeps microphone --- how can this be a bad thing? The current DPA problem surfaced just about a 2 months ago and is also being addressed by both Zaxcom and DPA. It should be noted that this comes after many years of ZERO problems with probably the best sounding lav there is coupled with the best sounding transmitter in the industry. 

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Thanks Jeff, I stand corrected. I was more or less hijacking this thread trying to get some resolution to the TRX 742 RF  issue which seems similar. I have personally never had any RF issues with any Lectrosonics wireless using them with all types of lav mics DPA included and Lectro plug-ons with Schoeps , Neumann, Sennheiser. I'm trying to move into some Zaxcom wireless but all this RF stuff has me spooked.

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"I have personally never had any RF issues with any Lectrosonics wireless using them with all types of lav mics DPA included and Lectro plug-ons with Schoeps , Neumann, Sennheiser."

 

The RFI problem is not a factor with Lectrosonics (analog hybrid) transmitters --- only with digital transmission.

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OK thanks for the clarifications guys.

 

My trepidation occurs when imagining  that conversation with the director or producer explaining why the last take is N/G and I need to swap out mics on the actors because of "Mic" RF issues and the reason I was using the Zaxcom (digital) radios in the first place was because of a marginal but definitely perceptable difference in quality....etc.etc.....a conversation I would rather not have.

 

As far as the plug on situation, according to threads on this site and Zaxcom's user site the RF issue occurs not only when the TRX 742 is plugged directly into the mic, which one would never do in practice, but when used near the mic such as with an Ambient Top Tip or even in some cases at the bottom of the pole. Most of my boom swingers like the TX on top of an uncabled pole. The reports say various Schoeps and Neumann mics have been problematic and vintage doesn't seem to be the determining factor.

 

Since Zaxcom is the only all digital system (that I know of) aren't we assuming the fix lies in the mics themselves and not something in the digital radio design? Pure speculation here because I am nothing close to an electrical engineer, just a monkey turning knobs and getting a paycheck.

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that conversation with the director or producer explaining why the last take is N/G and I need to swap out mics on the actors because of "Mic" RF issues "  and " The reports say various Schoeps and Neumann mics have been problematic and vintage doesn't seem to be the determining factor. "

well,  CRAP happens.

OTOH, if something doesn't work properly... don't use it.

I went to the Doctor the other day and told him it hurts when I bend my arm like (imagine it) this,  and he told me to not bend my arm like that...

I have...

and

...it has stopped hurting

 

and, BTW: " which one would never do in practice, " although another one might.

" aren't we assuming the fix lies in the mics themselves and not something in the digital radio design? "

some kids just don't play well together...they don't always get along.

 

" just a monkey turning knobs and getting a paycheck. "

and sometimes having unrealistic expectations ?

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"I have personally never had any RF issues with any Lectrosonics wireless using them with all types of lav mics DPA included and Lectro plug-ons with Schoeps , Neumann, Sennheiser." The RFI problem is not a factor with Lectrosonics (analog hybrid) transmitters --- only with digital transmission.
Well, ever since having gone down a similar route Geoff is now going down on, too (in the same thread even) I have been told that it doesn't really matter if it's digital or analogue or both.
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