Rasmus Wedin Posted October 2, 2010 Report Share Posted October 2, 2010 Hi I did this gig yesterday at a large conference center. For some reason I got major radio-interference on my boompole mic, wich was wired with a standard XLR. Meanwhile my wireless lavs were not effected at all, so strange. After checking all my gear I asked a guy who worked there and he tolled me they had a wireless internet access in that particular room I was getting interference in. Could that somehow have gotten into my boom signal, through the cable or maybe even the mic? I've never experienced this before. Thanks / Rasmus Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 2, 2010 Report Share Posted October 2, 2010 " Could that somehow have gotten into my boom signal, " yes Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted October 2, 2010 Report Share Posted October 2, 2010 Could that somehow have gotten into my boom signal, through the cable or maybe even the mic? I've never experienced this before. Thanks / Rasmus Yes, interference could happen, most probably from the microphone, if there is a strong WiFi RF field (2.4 ghz). Some microphones are more sensitive to this, some are almost immune. Older Schoeps microphones are quite susceptible to WiFi interference. - Jeff Wexler Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 2, 2010 Author Report Share Posted October 2, 2010 Yes, interference could happen, most probably from the microphone, if there is a strong WiFi RF field (2.4 ghz). Some microphones are more sensitive to this, some are almost immune. Older Schoeps microphones are quite susceptible to WiFi interference. I was using a Sennheiser mkh 50 on the boom and DPA-lavs, witch were uneffected. Is there anything you can do to counter these situations? Is this a common problem? I've never experienced it before, but I mean, WIFI is all over the place today. Quote Link to comment Share on other sites More sharing options...
jason porter Posted October 2, 2010 Report Share Posted October 2, 2010 if it wasn't the '50, maybe you have a break in the shield of the boom cable? Quote Link to comment Share on other sites More sharing options...
Jeff Wexler Posted October 3, 2010 Report Share Posted October 3, 2010 if it wasn't the '50, maybe you have a break in the shield of the boom cable? I think he was referring to the DPA lavs being unaffected. The original post clearly indicates it was the boom mic/fishpole that was affected. Quoting: "I did this gig yesterday at a large conference center. For some reason I got major radio-interference on my boompole mic" The boom mic was stated to be a Senn. -50 which is generally not very susceptible, I believe, to this sort of problem. Quote Link to comment Share on other sites More sharing options...
TomBoisseau Posted October 3, 2010 Report Share Posted October 3, 2010 if it wasn't the '50, maybe you have a break in the shield of the boom cable? If that were the case, the mic would not be able to receive phantom power. Tom Quote Link to comment Share on other sites More sharing options...
jason porter Posted October 3, 2010 Report Share Posted October 3, 2010 yeah, I got it...I was trying to say - if the mic wasn't the probable cause of the interference, maybe the foil/braided shield in the XLR cable has a break in it. Am I totally off-base here? I think he was referring to the DPA lavs being unaffected. The original post clearly indicates it was the boom mic/fishpole that was affected. Quoting: "I did this gig yesterday at a large conference center. For some reason I got major radio-interference on my boompole mic" The boom mic was stated to be a Senn. -50 which is generally not very susceptible, I believe, to this sort of problem. Quote Link to comment Share on other sites More sharing options...
jason porter Posted October 3, 2010 Report Share Posted October 3, 2010 really??? So, if I have XLR cables that do not have the shield tied to ground (on one end), it won't pass P48? I thought phantom was passed on pins 2&3 with pin 1 as drain/ground? If that were the case, the mic would not be able to receive phantom power. Tom Quote Link to comment Share on other sites More sharing options...
Eric Toline Posted October 3, 2010 Report Share Posted October 3, 2010 yeah, I got it...I was trying to say - if the mic wasn't the probable cause of the interference, maybe the foil/braided shield in the XLR cable has a break in it. Am I totally off-base here? As long as there's continuity in the shield the mic will work. Foil shielded cables are more for in house installs where you set it and forget it and use the drain wire under the foil wrap for the ground connection. Highly unlikely that a mic cable for field use has a foil shield as the foil does not stand up to well to the handling of field use. The OP might want to have a short xlr-f>xlr-m jumper cable with the ground attaced to the xlr case solder tab at the input/female end of the jumper in case you run into the same situation again.That could solve the problem.................................or not. Eric Quote Link to comment Share on other sites More sharing options...
Eric Toline Posted October 3, 2010 Report Share Posted October 3, 2010 really??? So, if I have XLR cables that do not have the shield tied to ground (on one end), it won't pass P48? I thought phantom was passed on pins 2&3 with pin 1 as drain/ground? You're correct Jason. You'll have phantom to the mic but no audio output. Eric Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 5, 2010 Author Report Share Posted October 5, 2010 I think he was referring to the DPA lavs being unaffected. Exactly. I found that weird since they have much thinner cables and should realy be more susceptible to this kind of interference. Maybe the "larger mic" (Mkh 50) acted sort of like a "Larger antenna" (rather than the smaller lav) and therefore picked up more interference? IDK, I'm realy running out of ideas here, as to what caused the preoblems, just hope I don't get it again. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 5, 2010 Report Share Posted October 5, 2010 " they have much thinner cables " size doesn't matter ! there is a lot of physics involved, and it can get complex! Quote Link to comment Share on other sites More sharing options...
wolfvid Posted October 5, 2010 Report Share Posted October 5, 2010 "major radio-interference" what did it sound like? "major radio-interference" like the stuff you hear on cheap cable TV lectures? or congress TV? CSPAN? prob PDAs carried by attendees..? coiled cables inside boompoles, ever so convenient are trouble... early Sennheisers had serious RF sensitivity, there was a manufacturers mod. if you had any kind of backup with you you can tell which part was the offending piece. make a recording available to this board and you will get good answers, not all this guessing. ALWAYS carry spare cables by a different manufacturer. skinny cables are suspect right out of the box. go back to the center and try new stuff..... shorter cables are better than long ones. I am guessing at an early Sennheissssser....... GUESSING you will have lost a client... Guessing don't get you tru a technical job for too long' and... All of Rwanda has good cell coverage on the main roads ( yes!) - near the cell sites you got a lot of RF, more than in the countries that have FCC like rules. wolf Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 8, 2010 Author Report Share Posted October 8, 2010 Im gonna be going back this monday, and gonna try some other mics, 416, 50. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 8, 2010 Report Share Posted October 8, 2010 " gonna try some other mics,... " ...different cables, etc. Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 9, 2010 Author Report Share Posted October 9, 2010 " gonna try some other mics,... " ...different cables, etc. I already tried differrent cables and also tried bypassing the boom, with the same result, so the problem is most likely in the mic. Now I'll just have to try to figure out how to solve it. Quote Link to comment Share on other sites More sharing options...
Eric Toline Posted October 9, 2010 Report Share Posted October 9, 2010 How old is your MKH 50? The newer RF proof 50's have gold xlr pins. The older versions have silver xlr pins. Eric Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 9, 2010 Author Report Share Posted October 9, 2010 How old is your MKH 50? The newer RF proof 50's have gold xlr pins. The older versions have silver xlr pins. Eric Thanks, thats a very usefull bit of info. I haven't got the gear here, but I'll check it first thing come monday. Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 12, 2010 Author Report Share Posted October 12, 2010 Update: Today I brought a couple of other mics to replace the 50-mic that was getting interference and also to test if more mics were effected på the wireless network. I brought two mkh 416 mics, another mkh 50 mic and a schoeps ccm41 LG. None of these mics were picking up any interference at all. Phu.... I asked if they had any goldplated 50-mics, but they were all out right now. However, my technical supervisor told me he had experienced similar interference with an old 50-mic picking up radio frecuencies and that it usually were the older ones that could have that problem. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 12, 2010 Report Share Posted October 12, 2010 " the older ones that could have that problem " the ones with out gold plated pins on the XLR's! just as has been already noted! Quote Link to comment Share on other sites More sharing options...
Rasmus Wedin Posted October 13, 2010 Author Report Share Posted October 13, 2010 " the older ones that could have that problem " the ones with out gold plated pins on the XLR's! just as has been already noted! Yes, but as I stated, I tried another 50-mic without gold plating and it worked fine. My point was that gold plating might not be a neccessity to get an interference-free signal, but it defenitly indicates a new, more Rf-proof mic, and is defenitly what to be looking for. Quote Link to comment Share on other sites More sharing options...
studiomprd Posted October 13, 2010 Report Share Posted October 13, 2010 That is correct, it isn't the gold plating on the pins, but the changes inside; the gold plating indicates newer production, many of the original production are also upgraded inside. Quote Link to comment Share on other sites More sharing options...
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