Chris Lowe Posted November 15, 2006 Share Posted November 15, 2006 hey im currently sound op for a small dance show in a local theatre. They have a very small budget and have got me 8 radio mics which are trantec and are unfortuantely VHF. I tried for UHF but they werent having any of it :( I have had nothing but problems with them since we started teching (which was yesterday). They keep dropping out and some of them are just crackling like hell. The antennaes are in the auditorium, which is only small, so I dont think the positioning is the cause, but there is definitely something amiss. Also the frequencies are far enought apart that there shouldnt be any conflictions there. I was wondering if anyone has used these or similar mics and knows any remedies to the situation. apart from chucking them away and getting sum UHF ones of course :huh: Any help would be greatly appreciated as im having a big ball ache of a time over this. Cheers Link to comment Share on other sites More sharing options...
dave singleton Posted November 15, 2006 Share Posted November 15, 2006 Ok, firstly am I the only one wondering why radio mics for a dance show?! And back on topic: Did you hire these mics, if so contact the place you hired them from. They will be able to offer support on the mics and send out replacements should there be problems etc. Alot of people complain about hires not functioning fully AFTER the hires been returned, which leaves the rental company no choice but to decline discounts etc unless something is very obviously wrong with what was sent out. Its not much help unless you tell them when the problem occures. Link to comment Share on other sites More sharing options...
paulears Posted November 15, 2006 Share Posted November 15, 2006 8 channels in VHF is pushing it unless you are using the full spread of channels. One thing to check is that you are not using two of the available channels that are not interference free - if the kit uses the older VHF channels they should include this set:173·800MHz, 174·100MHz, 174·500MHz, 174·800MHz 175·000MHz If you have another squeezed in here then this won't be intermod free - Trantec sold some on this odd frequency, which only works on it's own. You didn't say which systems you have, but the general rule is put the receivers as close to the stage as you can - back of the auditoriuym is really bad news. Keep the aerials away from sweaty skin and if the packs have dangly aerials, make sure they really are dangling, not scrunched up into a ball. You've obviously got the licence situation sorted haven't you? Did you buy them or hire them? Not really enough info - but adding 3 to the list above shouldn't be too much a problem. I'd guess 177.0, 177.6, 199.7, 200.3 would be likely frequencies supplied. If they drop out, but otherwise are solid, then it is signal strength in most cases, so move the receivers. Crackling sounds like dodgy cables while wierd noises is usually intermod interference. Link to comment Share on other sites More sharing options...
Ynot Posted November 15, 2006 Share Posted November 15, 2006 I'll go with Paul on the freq side of things. Don't be caught by the thought that just because the transmit freq's are separate that they can't interfere - it's not so much the separation but the intermodulation likelihood that will give problems. You need the RIGHT freq's for the job. And yes, 8 on VHF is definitely pushing the boundaries! Agree about the aerials as well.And if crackling is regular you should check whether it's the connector on the lead into the pack. The MOST common fault, in my exp, is a broken or frayed lead JUST by or inside the plug. Often this is caused by one of my all-time pet-hates, wrapping the cable round the pack when not in use... DON'T DO THAT and don't allow the talent to do so either! It's good practice to get some small cloth pouches - just slightly bigger than the mic packs, with velcro/press-stud to close it, and ties long enough to secure the pack around the waist of the talent. This helps secure the pack and keep it in place, but also stops too much build-up of sweat - another point Paul mentioned. TD Link to comment Share on other sites More sharing options...
lightsource Posted November 15, 2006 Share Posted November 15, 2006 And if crackling is regular you should check whether it's the connector on the lead into the pack. Also check that the gain is not set too high on your console, as this can also introduce distortion Link to comment Share on other sites More sharing options...
saturnx21 Posted November 15, 2006 Share Posted November 15, 2006 I was once told that induction loops for hearing aids can course problems for VHF radio Mic's although I don't know if that is true or not! :huh: Link to comment Share on other sites More sharing options...
Simon Lewis Posted November 15, 2006 Share Posted November 15, 2006 I was once told that induction loops for hearing aids can course problems for VHF radio Mic's Induction loops won't (unless they are malfunctioning!) generate RF. However, since they generate a magnetic field it's possible that this signal could be picked up by an audio circuit. It's not specific to VHF radios though... Link to comment Share on other sites More sharing options...
Shez Posted November 15, 2006 Share Posted November 15, 2006 Not that it's much help, but I'm very wary of working on shows if I don't know exactly what the kit is before taking on the work. Budget radios always cause grief and I don't like being put in a situation of having to blame the equipment as clients rarely understand that the kit that they've sourced & paid "a lot" of money for is rubbish. If they were cheap, they've probably been used (& abused) a lot; one side effect, as Ynot mentioned, is the crackling of dodgy mic leads (heard that regularly on local college dance shows...). If you can list the frequencies you've got, and also the exact model of the radio systems, we can probably offer more help. Link to comment Share on other sites More sharing options...
Chris Lowe Posted November 15, 2006 Author Share Posted November 15, 2006 thanks so much for all your replies. I cant actually tell you the frequencies im workin with today as I have a day off an cant get into the theatre but I can tell you that they are Trantec VHF Systems S3500. we are using 8 different frequencies with a hand held and a lapel mic on each frequency (but obviously not both on at the same time)! The woman who is runnin the performing arts school keeps asking me why the mics are doing what they are doin and I have told her that its because they are not as good as the ones they used last year (sennheiser UHF systems) and that we are using 8 of them when you really shouldnt use more than 3 or 4. unfortunately they are on a budget and have no extra money to hire proper ones! Link to comment Share on other sites More sharing options...
saturnx21 Posted November 15, 2006 Share Posted November 15, 2006 Simon Lewis Posted Today, 9:04 AM QUOTE(saturnx21 @ 15 Nov 2006, 12:38 AM) I was once told that induction loops for hearing aids can course problems for VHF radio Mic's Induction loops won't (unless they are malfunctioning!) generate RF. However, since they generate a magnetic field it's possible that this signal could be picked up by an audio circuit. It's not specific to VHF radios though... I was always unsure on that one but know I know! Thank you!!! :huh: Link to comment Share on other sites More sharing options...
Shez Posted November 15, 2006 Share Posted November 15, 2006 There are far worse mics out there than the S3500s. A few thoughts... Those receivers have captive antennae so I imagine you have a nest of 16 antennae all very close to one another - this is not ideal as they not only receive a signal but also act as mini transmitters which can wreak havoc with each other. Do you (or the hire company) have any licenced frequencies? I assume so as you can't operate 8 frequencies in the deregulated band. 8 in VHF will be a struggle regardless without intermodulation problems. The hire co should at least have tried to set them to frequencies that will play nicely. Is it only the lapel mics that crackle or do the handhelds also do it? If it's only the lapels, then as has been suggested, the mic leads have been abused and aren't in a good state. A conference speaker may not be as badly affected due to the lack of movement compared to a dancer so the problem may not have been apparent to the hire co before. Explain all of that to the lady in charge and suggest they allocate a more realistic budget if they don't want to put up with this again next time... Or use floats, shotguns etc which are a lot less hassle. Link to comment Share on other sites More sharing options...
paulears Posted November 15, 2006 Share Posted November 15, 2006 I'd like to state that the 3500 series is actually a very decent and properly designed system - and they were British too! They still OEM for others, including the Freedom Sennheiser range. The 3500 series has rear mounted RF sockets using TNC connectors. As we have said, Trantec have sufficient design stability to have 8 channels running trouble free, but they are using almost all the available channels. Sonically, I can't tell the difference between the sennheiser G1 or G2 and the Trantec VHF and UHFs. One comment, though about using handhelds and lavs on the same receiver. The handhelds need radical eq changes compared with the lavs - I've always found this quite difficult to do on an alanalogue desk. Typical faults on the lav packs are that the mic socket works slightly loose, this produces an intermittent crackle. Plug the lemo connector in and gently move it. Any play will be evident where the silver ring meets the plastic body. They come to bits quite easily with a jewellers crosshead screwdriver. just ease the daughter board out and you can get to the hex nut. check that there is a short earth strap still there - if the socket has been wiggling, sometimes the solder fails and the link becomes intermittent. Link to comment Share on other sites More sharing options...
Chris Beesley Posted November 15, 2006 Share Posted November 15, 2006 IfI read correct they are hired in ... Paul is spot on regarding the service of the mics - but best not to open the mics, instead get the hire co to do it for you. Link to comment Share on other sites More sharing options...
mackerr Posted November 16, 2006 Share Posted November 16, 2006 One comment, though about using handhelds and lavs on the same receiver. The handhelds need radical eq changes compared with the lavs - I've always found this quite difficult to do on an alanalogue desk.The easy fix for that problem is to use a twofer or a splitter and plug each receiver into 2 input strips, 1 for lav, the other for HH. Mac Link to comment Share on other sites More sharing options...
Ynot Posted November 16, 2006 Share Posted November 16, 2006 The easy fix for that problem is to use a twofer or a splitter and plug each receiver into 2 input strips, 1 for lav, the other for HH.Only easy though if they have 8 spare mixer channels, which I suspect they may not have.... (The OP said all 8 have both lav & HH) Link to comment Share on other sites More sharing options...
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