Craig A Posted July 23, 2014 Share Posted July 23, 2014 Hello Blue RoomHaving recently added four more to my system, I'm currently running 12 radio mics. We have a big show coming up and we would like to rehearse with all 12 mics sooner rather than later (to prevent as much of the fiasco from last year as possible!).I've been using 8 on a few shows with varying success. There's always one or two that seem to crack, cut out, lose quality etc but it is never the same one which leads me to believe it is signal problems. I have my mics set quite far apart frequency wise and it doesn't always solve the problem. I have heard that certain frequencies work better together but I cannot find any answers searching the web? Is there any truth to this? Are there any standard dos and don'ts when working with radio mics?Thanks in advance Link to comment Share on other sites More sharing options...
GR1 Posted July 23, 2014 Share Posted July 23, 2014 There are specific frequencies which can usually work well together. Just tuning them 'quite far apart' can be a recipe for disaster. The manufacturers websites usually publish lists of frequencies which will work together. If you are using a mixture of radio mic types that can complicate things. You need to provide more details of the equipment you are using and the frequencies it is tuned to. Link to comment Share on other sites More sharing options...
Mr Steve Posted July 23, 2014 Share Posted July 23, 2014 If these are Sennheisers on channel 38 (606-614MHz), then the following will work together: 606.500607.357608.000611.000611.400613.275606.875608.425609.325609.775610.475612.000 Spreading them out in even chunks, or far apart, has no bearing on whether or not you will experience problems. Link to comment Share on other sites More sharing options...
paulears Posted July 23, 2014 Share Posted July 23, 2014 Don't forget that brand x safe frequencies will be different for brand y. Mixing brands often means a totally unworkable system. Link to comment Share on other sites More sharing options...
pete10uk Posted July 23, 2014 Share Posted July 23, 2014 If these are Sennheisers on channel 38 (606-614MHz), then the following will work together: 606.500607.357608.000611.000611.400613.275606.875608.425609.325609.775610.475612.000 Spreading them out in even chunks, or far apart, has no bearing on whether or not you will experience problems. I stick to these Sennheiser frequencies with my Sennheiser kit and have very few issues. On the odd occasion I do have frequency problems, I don't find that the issue manifests as a crack or cut out but more of a whisper / Shusssss type of noise. I tend to find that crackle, pops and cutouts are lack of signal or bad connections / faulty cables. As mentioned by GR1, if you post a list of your kit, better advise will flow. Link to comment Share on other sites More sharing options...
Richard P-W Posted July 23, 2014 Share Posted July 23, 2014 As it brings out the OCD in me, can someone explain why the Sennheiser frequencies in a bank are not in ascending order? Is it to do with intermodulation as you add more into the channel? Link to comment Share on other sites More sharing options...
pete10uk Posted July 23, 2014 Share Posted July 23, 2014 As it brings out the OCD in me, can someone explain why the Sennheiser frequencies in a bank are not in ascending order? Is it to do with intermodulation as you add more into the channel? As this post reminded me not only to renew my Ch38 Licence but also to make some stickers to remind customers of the bank and frequencies to use, I checked through bank 1 this morning and that appears ascend in order. I will however point out an error in Mr Steve's post, the 607 frequency should be 607.375 not 607.357 - there you go that's my OCD showing. As it brings out the OCD in me, can someone explain why the Sennheiser frequencies in a bank are not in ascending order? Is it to do with intermodulation as you add more into the channel? As this post reminded me not only to renew my Ch38 Licence but also to make some stickers to remind customers of the bank and frequencies to use, I checked through bank 1 this morning and that appears ascend in order. I will however point out an error in Mr Steve's post, the 607 frequency should be 607.375 not 607.357 - there you go that's my OCD showing. Sorry Sorry Sorry I get what you mean, it ascends in 2 rounds. I'd guess at better inter modulation. I'd not noticed that before. Link to comment Share on other sites More sharing options...
sam.spoons Posted July 23, 2014 Share Posted July 23, 2014 Surely the reason for the non sequential frequencies is that you use the first six for best separation when you only have up to six mics and slot the next six into the gaps (with the increased possibility of intermodulation) if you need to run more than six mics? Link to comment Share on other sites More sharing options...
paulears Posted July 23, 2014 Share Posted July 23, 2014 My understanding is that Sennheiser work on the assumption that many people will not use all of them, and when calculating inter mod products, although the full list functions, better performance is likely with the first set. Adding in the rest degrades RF performance slightly, but is still ok. Even with th suggested frequencies, they cannot be clear of interference all the time in every location and permutation of equipment signal strength relative to others. Use the first suggestions first. Link to comment Share on other sites More sharing options...
Mr Steve Posted July 23, 2014 Share Posted July 23, 2014 I will however point out an error in Mr Steve's post, the 607 frequency should be 607.375 not 607.357 - there you go that's my OCD showing. Thanks Pete - clearly too early for my brain to communicate with my fingers properly! Sorry! :) Link to comment Share on other sites More sharing options...
Richard P-W Posted July 23, 2014 Share Posted July 23, 2014 Thanks, makes sense. I just growl inside every time I look at my rack of 8 receivers!! Link to comment Share on other sites More sharing options...
Craig A Posted July 23, 2014 Author Share Posted July 23, 2014 Thank you for all the help so far, I thought just keeping the signals apart would help!I didn't realise that manufacturers may publish radio frequencies so that's good to know. The Sennheiser frequencies will help as I have 4 gen 3s which have the preset banks anyway and also 4 xs series which I can set to them as well. However, I do also have 4 Audio Technica ATW-R3100 that we still use. How much more complicated will this make it to get them all working okay? Thanks again Link to comment Share on other sites More sharing options...
gibbothegreat Posted July 23, 2014 Share Posted July 23, 2014 Obviously wouldn't apply to Evolutions as they're all singles, but Shure certainly used to have a recommendation that you shouldn't programme adjacent frequencies in a twin receiver, IIRC they suggested a separation of at least 500MHz. Typically, I try run frequencies numerically in receiver order 1,3,5,7,2,4,6,8 or variations thereof. Link to comment Share on other sites More sharing options...
GR1 Posted July 23, 2014 Share Posted July 23, 2014 Are all thes 3 types of radio mic on Band 38? It sounds as though the Audio Technicas might be getting on and could be Band 69 which is illegal. If they are Band 70 or VHF that would help. More info please? Link to comment Share on other sites More sharing options...
Rob_P Posted July 23, 2014 Share Posted July 23, 2014 I had a mixed set of Chan 38 G3 (4 off) and XSW (2 off) on a job the other day and they seemed to work ok.Unfortunately (presumably due to differences in the RF circuit design) the XSW preset frequencies are slightly different from the G3 ones. I went for manually tuning the XSWs onto spare slots in the G3 frequency table which seemed to work with no problems.One interesting finding was that whilst the XSW system doesn't offer a pilot tone function, the XSW transmitters seem to transmit it. I was able to use some of the spare G3 receivers in the rack to pick up the XSW handhelds, even though the pilot tone detection was turned on!Craig- If the AT mics are on Chanel 70 then they should be far enough from the other mics to not be an issue. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.