mcwillt05 Posted June 11, 2013 Share Posted June 11, 2013 I had a major problem with a set of Sennhensier sk300 G3 wireless bodypacks. When I was doing a production show where 6 wireless mics were being used. Got about halfway through the show and one mic started popping, Then led to all 6 of them randomly popping. Even receivers where the microphone was not turned on started to flash on and off. It seemed like some kind of interference within the frequencies. We are using a licensed frequency so should not get any interference. Even when I got all the singers to change to the handheld version of the same mic there was still some kind of popping going on,If any one has any ideas why this was happening please help, got another show tonight!Thanks,Tom Link to comment Share on other sites More sharing options...
pete10uk Posted June 11, 2013 Share Posted June 11, 2013 I had a major problem with a set of Sennhensier sk300 G3 wireless bodypacks. When I was doing a production show where 6 wireless mics were being used. Got about halfway through the show and one mic started popping, Then led to all 6 of them randomly popping. Even receivers where the microphone was not turned on started to flash on and off. It seemed like some kind of interference within the frequencies. We are using a licensed frequency so should not get any interference. Even when I got all the singers to change to the handheld version of the same mic there was still some kind of popping going on,If any one has any ideas why this was happening please help, got another show tonight!Thanks,Tom "popping" sounds like dodgy mic cabling, but 6 all at once seems unlikely. Are you sure it was the mics and not the PA when the tea urn thermostat was cutting on and off maybe? When you say receivers started to flash on and off even though the tx was off do you mean red and amber flash or completely on and off? the red amber flash is quite normal when using multiple systems at the same time, make sure your desk is down or on mute or leave the TX's powered on and just use the mute. I had a major problem with a set of Sennhensier sk300 G3 wireless bodypacks. When I was doing a production show where 6 wireless mics were being used. Got about halfway through the show and one mic started popping, Then led to all 6 of them randomly popping. Even receivers where the microphone was not turned on started to flash on and off. It seemed like some kind of interference within the frequencies. We are using a licensed frequency so should not get any interference. Even when I got all the singers to change to the handheld version of the same mic there was still some kind of popping going on,If any one has any ideas why this was happening please help, got another show tonight!Thanks,Tom "popping" sounds like dodgy mic cabling, but 6 all at once seems unlikely. Are you sure it was the mics and not the PA when the tea urn thermostat was cutting on and off maybe? When you say receivers started to flash on and off even though the tx was off do you mean red and amber flash or completely on and off? the red amber flash is quite normal when using multiple systems at the same time, make sure your desk is down or on mute or leave the TX's powered on and just use the mute. Tea urn scenario would explain why it only happened later on as for the first half it would have been on constantly getting the water to the boil. It also wouldn't happen in rehearsal. Link to comment Share on other sites More sharing options...
Nicktaylor Posted June 11, 2013 Share Posted June 11, 2013 I do aprreciate you say licence frequency, but I assume you mean frequencies? It does sound to me like you have some intermodulation and the popping is the mute cutting in and out. Did you set up frequencies as suggested by Sennheiser? Six channels should have no issues with not working together. Where were the packs on the actors? As the show goes on sweat can have an adverse effect on aerial radiation etc Link to comment Share on other sites More sharing options...
mcwillt05 Posted June 11, 2013 Author Share Posted June 11, 2013 I do aprreciate you say licence frequency, but I assume you mean frequencies? It does sound to me like you have some intermodulation and the popping is the mute cutting in and out. Did you set up frequencies as suggested by Sennheiser? Six channels should have no issues with not working together. Where were the packs on the actors? As the show goes on sweat can have an adverse effect on aerial radiation etc Yeh the frequencies are st up to the preset Sennheniser channels. 1.1 too 1.8. The packs are in fabric pouches on the back of the singers and dancers. The seat problem is very likely to occur as they are doing a full on dance routine for 45 minutes. Is there anyway of stopping the sweat from effecting the packs? When you say receivers started to flash on and off even though the tx was off do you mean red and amber flash or completely on and off? the red amber flash is quite normal when using multiple systems at the same time, make sure your desk is down or on mute or leave the TX's powered on and just use the mute. When I say the recivers started flashing, a reciver that had no microphone on on that frequency started flashing on and off, like some other transmitter was interfering on that frequency. Any channel that is not being used is always muted on the desk but they stay un-muted on the pack, or I have the usual problem of peole walking on stage when they are still muted on the pack! Link to comment Share on other sites More sharing options...
pete10uk Posted June 11, 2013 Share Posted June 11, 2013 When I say the recivers started flashing, a reciver that had no microphone on on that frequency started flashing on and off, like some other transmitter was interfering on that frequency. Any channel that is not being used is always muted on the desk but they stay un-muted on the pack, or I have the usual problem of peole walking on stage when they are still muted on the pack! This is normal operation, I have this all the time especially if I leave a spare TX close to the RX's. Is there a Tea urn? Link to comment Share on other sites More sharing options...
Shez Posted June 11, 2013 Share Posted June 11, 2013 Yeh the frequencies are st up to the preset Sennheniser channels. 1.1 too 1.8. Which band are your systems on? A? B? E? GB? The preset numbers are meaningless without knowing which system it is. Assuming that it may be a GB band and that you're running in Ch.38, it's worth remembering that that band operates on a shared basis - anyone with a licence can use it. The venue next door to you could also have been using those same frequencies legitimately which could explain your problems. Link to comment Share on other sites More sharing options...
ninjadingle Posted June 11, 2013 Share Posted June 11, 2013 Assuming GB Ch 38 frequencies 1.1 to 1.8 are as shown here And using Audio Technicas frequency compatibility checker hereChecking Frequency Compatibility The following frequency-pairs are likely to cause interference for some of the operating frequencies that you have entered. Frequency A. Frequency B 607.375. 606.500 607.375. 608.000 607.375. 606.875 607.375. 608.425 606.875. 606.500 606.875. 607.375 To correct this, one (or both) of the indicated frequencies in each pair listed below must be changed. First change the frequency that appears most often and run the test again. (This process should be repeated until a combination of interference-free frequencies is found.)Maybe not use 1.2 and 1.7? Repost for iPad not doing spacing correctly! Link to comment Share on other sites More sharing options...
Shez Posted June 11, 2013 Share Posted June 11, 2013 And using Audio Technicas frequency compatibility checker Alas, just as mixing and matching different brands of transmitters and receivers doesn't work well, neither does using one brands frequencies with another's hardware. Better hardware with steeper RF filters allow you to get away with frequencies that won't play as nicely with less well designed kit.I've used that frequency set before without issue, as I'm sure have many others. Link to comment Share on other sites More sharing options...
Oldradiohand Posted June 11, 2013 Share Posted June 11, 2013 If you are using ch38 then anyone else using ch38 mics nearby can legally interfere. If all the mics are popping at once it's probably mains borne or broadband interference (like a flickering flourescent tube). Of course, it could be something producing illegal interference - do the DTI still investigate this? Link to comment Share on other sites More sharing options...
pete10uk Posted June 11, 2013 Share Posted June 11, 2013 It's quite unlikely that 6 out of 6 frequencies have the same interference unless your in a crowded area. The interference I hear most often is wining noise rather than a pop, I use g3 300 mics on the sennheiser recomended set of frequencies. I don't often have any issues but when in a busy area can get 1 or 2 frequencies with issues, normally the lowered ones. I really think it is most probably mains related issues through the PA. Link to comment Share on other sites More sharing options...
chelgrian Posted June 19, 2013 Share Posted June 19, 2013 It's quite unlikely that 6 out of 6 frequencies have the same interference unless your in a crowded area. The interference I hear most often is wining noise rather than a pop, I use g3 300 mics on the sennheiser recomended set of frequencies. I don't often have any issues but when in a busy area can get 1 or 2 frequencies with issues, normally the lowered ones. I really think it is most probably mains related issues through the PA. From personal experience the other thing that can cause this is broad spectrum interference being emitted from a faulty belt pack. I had something very similar happen to me during a production where a belt pack got damaged by sweat. A bunch of fault finding later lead me to discover that the problem only happened when one particular belt pack was switched on regardless of the frequencies involved. Link to comment Share on other sites More sharing options...
Rob_Beech Posted June 20, 2013 Share Posted June 20, 2013 Interesting to hear about a potential faulty beltpack. Worth remembering. As other have said though, I think it's quite likely that the radio microphone systems themselves are potential red herrings and that the problem may lie elsewhere. Be it another device causing electrical interference or other systems in the area causing RF interference. I went through 3 conference rooms yesterday to check peoples frequencies and actually found that regardless of licensing, everyone else was using random stuff thrown over 40 41, 67, 69 still, the odd one in 44. So I threw my 8 channels on 1.1 to 1.8 in GB band and got on with it. Do you get any issues if every single transmitter you have is switched off? Link to comment Share on other sites More sharing options...
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