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November 9, 2012 at 3:55 AM #51864
I have a Sennhesier G3 on camera receiver and body pack transmitter.
The trasmitter combines a single mic and line input (mini jack).
Question is can the transmitter be plugged into a sound system output (for example that of a DJ at a wedding reception) so that speeches can be captured directly into the camera? This assumes the frequency is different from the DJs wireless equipment. If the answer is affirmative what output would be safe to use to prevent damage to the transmitter or sound distortion? If successful this would obviously solve a few problems.
November 9, 2012 at 6:29 AM #204779BruceMolParticipant
I've done that a number of times but you do have to mind the levels. I switch my camera input to LINE and I also carry adaptors for various mixing boards, both XLR and 1/4 inch. Some mixing boards can supply a 'house mix' for multiple inputs so watch for that if there is more than one person on the mic. Usually at weddings etc. there isn't but interview panels can pose problems.
November 9, 2012 at 6:41 AM #204780gldnearsMember
" . . can the transmitter be plugged into a sound system output . . "
There are those on this list who will warn against this solution based upon the grounds that you may not always be assured that whomever is operating the sound system will have your best interest to heart. Ideally, you are looking for a " line level " ( as opposed to mic level or speaker level ) output from the mixing console which duplicates the mix being sent to the speakers. Often this output will have its own volume control, which is a potential source of trouble for you.
You need a short ( three or four feet ) patch cable which has the proper console connector ( whatever that may be ) on one end and the proper connector for your wireless transmitter on the other end. You need to go into the setup menu on your transmitter and turn down the audio sensitivity to the point where the signal from the mixing console doesn't overload the transmitter; or for that matter, it needs to be lowered even more so that the signal from the mixer doesn't cause too much compression or limiting in the transmitter. All of this needs to be determined before show time. And then, place a piece of tape over the knob on the mixing console which controls the volume of the signal being sent to your transmitter.
If the mixing console doesn't have a line level output which has the same mix as that going to the speakers, the mixer will likely have an aux or effects mix bus where you can set up your own mix, but this is cumbersome and time consuming.
Either way, the quality of a console feed is vastly superior to a mic set in front of a speaker!
November 9, 2012 at 7:40 AM #204781
Thanks Bruce and Rick,
Seems that the risks are worth the overcoming. I think the best is to do tests in a non hostile or critical situation before committing to a wedding or other event. The gist seems to be have the right adaptors and make sure the audio levels are under control.
November 9, 2012 at 9:00 AM #204783paulearsParticipant
You mean the speeches are being run through the DJs mics, and then into a PA? If that's the case, the output at line level can go into the sennheiser transmitter – making sure you use the line, not mic socket connection.
If you want to use your Sennheiser receiver to receive the output from the DJs mic direct – as in his receiver goes to the PA and your receiver gos to the camera, then it's more complicated.
If you switch off the pilot tone on the receiver, you can tune it to the same channel as the DJ is using (assuming of course that his system has a frequency display (Shure often give channel, rather than frequency display – you could search for it, I guess, if you have time).
This does NOT guarantee good results. Most radio systems use companding to get better signal to noise. Each manufacturer has a slightly different system. In practice, it often works – and is worth attempting. Sometimes the two systems just don't match properly and you get very 'spikey' audio with huge peaks and troughs. Other times, the mismatch is quite pleasant sounding.
The other technical difference is that the bandwidth will no doubt be different, and if this doesn't match you can get either very low level hissy audio, or nasty distorted peaking.
If they have a Sennheiser system, then it will be fine. If they have something else, it's possible.
However – their systen could be in a different band to yours, and if that's the case, you are stuffed!
November 10, 2012 at 6:06 PM #204794JackWolcottParticipant
Please DO NOT under estimate the dangers involved in this. We often work with professional, union audio people who, with the best of intentions, still mess up. The board operator is concerned with lots of things and, unfortunately, you are usually dead last on his list. A couple of shoots ago, after running a thorough sound check with the board op, my camera was hit with such a blast of sound that I thought I would scream. My ears rang for several minutes. Turned out he had turned up the wrong pot, sending me a signal that was nearly 10 times what we had set. He apologized after the show, but 1) my camera could have been ruined and 2) I lost all audio for about 5 minutes of the production.
Set up your camera with attenuation before you get a signal from the board. Set up the camera for line level input (the hottest signal will be line level) and the attenuation should protect against overload to the camera. If you don't hear anything, then switch to mic level and, finally, remove attenuation. To be on the safe side, I have a couple of in-line attenuators — you can get them at Radio Shack, Markertek, B&H, etc., — that will take down the sound level even more than your camera attenuation will.
The trick here, to protect your gear, is to hasten slowly. It takes time to get it set up properly; do a careful sound check before the shoot begins and make sure the sound operator fully understands how much damage can be done to your camera (and your ears) if he botches the job.
November 11, 2012 at 7:01 AM #204799
Thank you Jack.
The experience-based quality of response received to my question reminds me of the value of Videomaker membership. Rick also mentioned the dangers of relying on the sounde operator and his suggestion of taping the control for the selected channel is wise providing the operator is one of the helpful variety. Quite a lot to work through! I hadn't thought about attenuators and will investigate this route. Since you hint at removing the attenuator once you've got the sound under control I'm wondering if the attenuator influences the sound quality?
Regards & thanks,
November 11, 2012 at 8:38 AM #204800gldnearsMember
Jack may have overlooked the fact that you'll be sending the console mix to your Sennheiser wireless transmitter and not directly to your camera. Obviously, nothing will change in the relationship between your wireless receiver and your camera . . . . BUT there may exist a volume level to the input of your wireless transmitter which could result in damage. In fact, there may be a specification in your Sennheiser manual, or you could contact Sennheiser to ask them how much is dangerously too much. I suspect the actual limit to the level you can feed the transmitter before damage just might be more than one would suspect. If I'm correct, the volume adjustment on the transmitter deals with the modulation level within the transmitter and leaves the input stage ( preamp ) unchanged/unprotected. Therefore, it should be okay to drive the transmitter with a line level signal without a pad inserted, but surely a -10 to -15 attenuater would be a reasonable precaution. At least, in the unlikelyhood your transmitter becomes toast you still have a fully functional camera!
November 11, 2012 at 12:31 PM #204802JackWolcottParticipant
Good points, Rick. I had missed the bit about feeding the transmitter rather than directly into the camera.
I guess I'd have to say that in general I hate relying on board feeds, just because your audio is out of your direct control. We've had shoots go completely sideways because of problems with the board feed and now factor into our billing our own audio technician. We may still be using the board feed, but with our tech overseeing what's going on, assuring that we're getting what we need when we need it.
November 14, 2012 at 4:48 PM #204840channeloneParticipant
[quote=Alexian] If the answer is affirmative what output would be safe to use to prevent damage to the transmitter or sound distortion? If successful this would obviously solve a few problems.
I have done this many times and yes you can connect the G3 to a board keeping in mind you will need to adapt the G3’s 3.5 mm jack to the available output of the board and that is where things can get a strange, normally on a pro board you might find an XLR output, on a prosumer board maybe a ¼ inch TRS and on a DJ consumer board it could be a standard RCA connector or who knows.
As such you will either need a bag full of adapters or as I would strongly suggest you meet with the board operator or Dee Jay in advance and see what he can offer you.
A perfect example of how un-planned things can get Murphyed and you don’t want that to happen is where I recently assisted a crew from Channel 4 UK’s program Unreported World who was over here doing a piece on talk radio and American politics, the camera man had plenty of XLR gear and the radio station utilized a pro board, but the stations policy was NO ONE connects to the on-the-air board and she was directed to connect to a headphone output, which lacking a TRS to 3.5 mm adapter for her G3 or a TRS to XLR for her camcorder found her back to the wall.
To solve the problem for her I ran the headphone output through a passive direct box and then handed off it to her with a TRS to 3.5mm adapter cord, the PDB matched the low impedance of the headphone to the high impedance of the G3 and all went well.
As for the levels of your G3 it is looking for a nominal 1 volt peak to peak consumer line level and it will tolerate up to 3 volts PTP before going all to heck, as such a pro line output is tolerable, a TRS main output is cool and a cranked down headphone output utilized with a PDB will work.
By the way there is nothing off of a non-amplified board that will damage your G3 though a too high level will be quite distorted, that stated unless you have a good idea of what you are connecting to always AVOID any direct connection to a speaker output.
As for BO’s while many of them know their art they are generally not technicians as such they many times will not know the level and impedance of the output they are offering youas that is your job to understand, so here are the basics.
If the BO provides you with an XLR output it will generally be line level, but low impedance and at a level lower than consumer, the good news is you can patch the G3 into it, is not a good match it will be low, but it will work.
If the BO provides you with a main or aux TRS or RCA output you should be good to go, do a sound check and ask him to politely to lock/tape the send.
If all the BO can provide you with is a headphone output, politely ask him to show you the level control of the headphone distribution amp related to the port you are connected to and utilizing a PDB and after your sound check levels are correct temporally place a strip of gaffers tape over that pot on the amp.
November 14, 2012 at 4:48 PM #204841channeloneParticipant
[quote=JackWolcott] My ears rang for several minutes. Turned out he had turned up the wrong pot, sending me a signal that was nearly 10 times what we had set. He apologized after the show, but 1) my camera could have been ruined and 2) I lost all audio for about 5 minutes of the production.[/quote]
Unless you are jacked into amplified/speaker output from a board there is no way a line level output can damage the input of a camera.
At worst it will go to total clipping which sounds rough but like many urban legends such as taping arc welding it is harmless to the equipment…
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