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4g Pushed Me Out?

xd-v70l dropouts rf help 4g distortion question problem

Best Answer charlesvk , 25 November 2013 - 04:13 PM

Maybe we´ll have the good fortune of grabbing a nice cup of coffee together one day :D

 

Just got back from Brussels: everything was crisp and clear, using our own setup. No problems whatsoever!

 

Maybe I´ve misread your answer on this, but the tech meant power groups, not audio groups.

 

Anyways, I think we can conclude it was the venue, nothing else. Might they ask us back, we´ll make sure get all of our gear out the van this time!

 

Thanks to the both of you for thinking here with me!

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#1 charlesvk

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Posted 23 November 2013 - 02:31 AM

Hi,

 

We use two XD-V70L systems for a couple of years now with great satisfaction. Yet yesterday, for the first time, we got into big trouble right before the start of a show at a high school in Amsterdam.

 

At the end of the day before the show we did a soundcheck: everything OK. We returned the next morning and our sound was completely distorted and we faced audio dropouts on the XD channels as well. Then I noticed the receivers showed RF signals coming in, even though the belt packs were turned off. Up to 4 LED´s! Disconnecting them from my console (and using a pair of good old SM58´s) saved our show.

 

The local technician told me they had a new 4G router installed (which wasn´t operating during the day of the sound check, hence). He said they faced trouble themselves with their Sennheiser UHF systems since they got this new router.

 

Q1: I thought I was save from all this frequency hassle, but am I not??? (No probably)

Q2: I understood there was secure/locked/shielded communication between the receiver and the belt pack. Does this new 4G network send such strong signals, it can override/break in anyway? (Yes, apparantly)

Q3: The distortion affected my whole system: everything got distorted (music coming in on other channels as well)! Even though the incoming XD channels were muted! How is this possible?

Q4: What to do to solve it or are we screwed?

 

If anyone has any suggestions, please let me know.

 

Kind regards,

 

Charles

 


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#2 RonMarton

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Posted 23 November 2013 - 09:06 AM

...The local technician told me they had a new 4G router installed (which wasn´t operating during the day of the sound check, hence). He said they faced trouble themselves with their Sennheiser UHF systems since they got this new router...

 

Gosh Charles...

 

:(  :wacko:

 

…I regularly operate the RF1 scheme for my eight XD-V70 (plus one XD-V75) systems in close proximity to 4G and 3G equipment, with NO problems whatsoever...

 

BUT...

 

…That local technician's report of reputable UHF gear also being "trodden on" by the new installation, plus your report of music "breaking through", makes me think that it's radiating all sorts of "junk" that has nothing whatsoever to do with 4G.

 

Even so, I would have expected RF1 to cope, …provided our individual transmitter to receiver "pairings" were performed at close range and then maintained (albeit at greater distances) for the entire performance.

 

You were running RF1, weren't you ?


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#3 dboomer

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Posted 23 November 2013 - 09:18 AM



Something else is happening. Especially if all the rest of your system is affected. 4g nor anything else can cause distortion to Line 6 wireless. It may be inserting junk into your cables maybe. Maybe it's getting into your power source if it's affecting everything.

It is probably not affecting your XDV's at all unless it is very close to the receiver's antennas. What firmware version are you running? I'm assuming that you are running in RF 1 mode because you couldn't do anything else unless you have upgraded to v2 firmware ( which I would recommend doing ... But likely still running in RF1mode)

#4 charlesvk

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Posted 23 November 2013 - 10:15 AM

Hi,

 

Thanks for your replies.

 

To tell you the truth, I don´t know whether I´m running in RF1 mode (but apparantly I am), nor did I know you could actually upgrade the firmware or how. I´m an actor/musician and got the gear working, so didn´t have to do anything more (which is a compliment to you guys  :) ).

 

Now I can´t find this in the manual either. I´ll try to find this on your site, but if you can provide me with a link to/procedure on how to upgrade the firmware, that would be much appreciated.

 

I used a 380V to 3 x 16A power outlet with nothing else on it except my gear, where it first goes to a Furman, which read as usual. Besides that, I changed the power with a "regular" single 16A group to check that as well. So power should have been good.

 

The thing is, my console, gear and the receivers are built in a flight case, which I keep on stage. So the distance between the belt packs and receivers are minimal. The local console (and router) were in the back of the theatre, so there was quite some distance from the receivers antennas as well. Like said, RF lit up several LEDs in red. Pulling out the XLR cables which connect the receivers to my console got rid of the distortion on every channel and gave me a clean sound again. Using balanced audio cables throughout, btw.

 

Thus leading to my conclusion above that the interference the receivers picked up, caused the distortion.

 

Please let me know if you have more information/ideas.


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#5 charlesvk

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Posted 23 November 2013 - 01:10 PM

If I understand correctly I cannot upgrade to firmware 2.0 ???


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#6 RonMarton

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Posted 23 November 2013 - 03:45 PM

Last one first, Charles...

 

…Only because it's the easier of the two !  :)

 

If I understand correctly I cannot upgrade to firmware 2.0 ???

 

You certainly "can", but (as Don has already hinted) my feeling is that, given your situation, there are two reasons that I'd simply stick with RF1 and so would NOT bother with the upgrade, being:

  1. The extra flexibility and extra two channels provided by RF2 (taking the total to 14) come at the "cost" of more "fiddling" and a greater chance of RF difficulties should the channel allocation process not be properly carried out for a given venue  …and...
  2. The Line 6 "Monkey" upgrade process for your two XD-V70L's requires access to a V75 receiver. 

This TBP12 video will quickly give you an idea of what's involved:

 

http://line6.com/sup...itter-tbp1-r544

 

Now, back to our original problem...

 

...The local console (and router) were in the back of the theatre, so there was quite some distance from the receivers antennas as well. Like said, RF lit up several LEDs in red. Pulling out the XLR cables which connect the receivers to my console got rid of the distortion on every channel and gave me a clean sound again. Using balanced audio cables throughout, btw...

 

If a better description of an "earthing difference" problem being introduced by a venue having incorrectly configured wiring (between the performance area and the FOH console, and/or locally at that console) actually exists, …I've yet to see it. :lol:

 

No wonder the venue's own receivers (among other sources) struggle with a whole variety of RF problems that would only have been "capped off" by the switching on of their new 4G router.

 

It's very rarely possible for this forum's contributors to offer more than opinions, but in this case I'm happy to report a rock-solid, dead-set-certain, ironclad-guaranteed FACT...

 

The only possible "cure" for the incompetent installation in that venue would have nothing whatsoever to do with your power-conditioned XD-V70L and console "rack".

 

It would be this...

  1. Total disconnection of all wiring (including mains power) at their console and/or between their console and their performance area and
  2. Subsequent replacement of that wiring by correctly configured cabling, (including those mains powering arrangements) be that correctly configured replacement on a "show-by-show deployment" basis, or permanently installed.

Now all we need to do is figure out how you can get the consultancy fee the high school owes you for diagnosing their difficulties. :)


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#7 dboomer

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Posted 23 November 2013 - 04:55 PM

Seeing red RF LEDs when the transmitters are off is typical and doesn't indicate the presence of problems.

I'm interested your later post says when you disconnect the outputs from the L6 receivers the clean sound comes back.
1. If you plug them back in does the problem come back?
2. If so does it happen with he transmitters both turned on and turned off?
3. Do your XLR cables have pin 1 tied to the shells?
4. You also need to check and see if the problem happens if you physically plug the receivers and the mixer into the exact same AC service.

I don't think you have any problem with the receivers but something changed in your system and you now have a "system" problem.

#8 RonMarton

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Posted 24 November 2013 - 01:58 AM

This was the "clincher" for me, Don...

 

...We use two XD-V70L systems for a couple of years now with great satisfaction. Yet yesterday, for the first time, we got into big trouble right before the start of a show at a high school in Amsterdam.

 

...I don't think you have any problem with the receivers but something changed in your system and you now have a "system" problem.

 

…Agreed,

 

…But I think that (on reflection) you'll also agree that it's almost out of the question for that problem to actually reside in or with Charles' own "system", a "package" that has (for such a long time) been the basis of his hitherto trouble-free touring show.


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#9 charlesvk

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Posted 24 November 2013 - 02:13 AM

After we made a new show about a medieval story some 8 years ago, several teachers started asking if we could perform at their high school. We were assured they had good sound systems and so we went, bringing a CD with us. Little did we know... I could tell you the most crazy stories of what we´ve encountered over the years, but you´ve probably experienced/heard those in one way or the other. Anyway, very soon I started studying and investing in gear. Nowadays we come with a van and bring our own sound system. We even bring a broom, cleaning spray and our own coffee machine (which I can really recommend btw!).

 

Yet at this particular school we walked in a jaw dropping theatre with an EAW array, Yamaha digital console etc. Never seen that before in a school. So I said: let´s leave our PA in the car. Well, lesson learned.

 

And recently I really did think of offering schools consultancy about their audio. It´s crazy to see how much money they spend on such poor sound. But, even while I get much compliments about my sound, I have no knowledge of electrics, wiring and such. Which brings me to Dan´s reply:

 

1. Yes, tried that.

2. Yes

3. They are good quality ready made cables, according to their schematics, yes (http://www.adamhall....erm=KCREF735150)

4. I guess you mean the mixer of that venue, since my mixer and receivers are built in the same rack? I can´t check that anymore. I now remember though, that I asked the technician if it was save to turn on my gear, without causing a big popping noise. He said that there should not be any problem, since they were on seperate groups. That probably answers your question?

 

Do I understand correct then, that RF interference can be caused by bad wiring/electrics?

 

I´m starting to think too, that it was a system problem. This would be a big relief, since their system is not a part of my system. Which means it should be solved. I´ll find out tomorrow: next show in Brussels. Though they probably won´t have any 4G routers there. But since what you´ve said, that should be not likely to have been the problem from the start.

 

I´ll let you know how it went.


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#10 dboomer

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Posted 24 November 2013 - 07:59 AM

Ok ...

Your answer to #2 rules out RF interference from the XDV's radio section. When the transmitters are turned off the output is turned off and disconnected ( with the exception of the ground connection). It is possible that interference can penetrate the cable itself you will just have to trace that out.

I'm not seeing a schematic of the cable from your link. But if pin 1 is connected to the shell some mixers will have problems with that ... Especially if phantom power is turned on ( which I didn't ask about).

What I'm trying to determine from #4 is that ALL connected gear is at exactly the same ground potential. Being there is some distance between the two I doubt that they are. I suspect that your system connected to the house system is where the problem actually lives but all I can give you is my best guess.

#11 charlesvk

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Posted 24 November 2013 - 09:09 AM

So, you´re saying that - with the transmitters turned off - the cable might have picked up interference, causing the distortion and lead to the red LED´s to appear? Is that likely with a 1,5 meter balanced cable?

 

It´s the second picture (not directly in sight; click on the 2). I guess that what you call "shell", they call "shield" right? Or am I wrong about that?

 

The tech said phantom power was turned off.

 

I understand what you´re trying to dertermine. Like the tech said, there were different groups, so I guess that means different grounding as well?

 

Could it have to do with the wall warts of the receivers not being grounded as well?


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#12 RonMarton

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Posted 24 November 2013 - 11:30 AM

I don't know if I can be clearer...

 

…But I will try.  :lol:  :blink:

 

There is NOTHING, repeat …NOTHING wrong with YOUR equipment, Charles !

 

The basis for my first reply to your post was over forty years of ongoing professional experience, worldwide, as a Sound Supervisor/Audio Director/Tonmeister in television, film, theatre and recording, informed by my analysis of the excellent "background" information you set out when you started this topic.

 

So I really, really, MEANT this...

 

...If a better description of an "earthing difference" problem being introduced by a venue having incorrectly configured wiring (between the performance area and the FOH console, and/or locally at that console) actually exists, …I've yet to see it...

 

…when I said it.  :)

 

All of the additional comprehensive information that you've so carefully set out since absolutely confirms what I originally said.

 

...Like the tech said, there were different groups, so I guess that means different grounding as well?...

 

No, the tech's answer only refers to the path taken by your signals within his console.

 

...Could it have to do with the wall warts of the receivers not being grounded as well?

 

Definitely not.

 

Indeed that independence from mains earth can often be but one of many reasons why XD-V systems are normally so trouble-free when compared with some other wireless systems.

 

Trust me when I say that the faulty wiring at the school in question has effectively "sabotaged" their investment in top quality equipment, every bit as surely as loading your trusty (and, to my mind, absolutely vital) coffee machine with inferior coffee would negate the very reason for its purchase.

 

Mine's a short black, by the way, …maybe with just a drop of milk if it's the second, (or third) following our "bump in" and rig. :)


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#13 charlesvk

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Posted 25 November 2013 - 04:13 PM   Best Answer

Maybe we´ll have the good fortune of grabbing a nice cup of coffee together one day :D

 

Just got back from Brussels: everything was crisp and clear, using our own setup. No problems whatsoever!

 

Maybe I´ve misread your answer on this, but the tech meant power groups, not audio groups.

 

Anyways, I think we can conclude it was the venue, nothing else. Might they ask us back, we´ll make sure get all of our gear out the van this time!

 

Thanks to the both of you for thinking here with me!


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