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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: frank kayser on May 01, 2014, 02:34:23 pm

Title: Wireless from board to camera?
Post by: frank kayser on May 01, 2014, 02:34:23 pm
Well folks,
Got a job where they want to videotape some acts on the stage.  I can set up an aux easily enough (pre fade, post eq) via XLR - done that before. - they want to go wireless.  I know something exists -
I'm guessing it would be similar to a wireless monitor feed - but different.


Any clues as to what the something and if it is something that can be rented?


frank
Title: Re: Wireless from board to camera?
Post by: Jay Barracato on May 01, 2014, 05:56:53 pm
Just find out what type of plug on the camera, then it is just mini plug from the iem to the camera.

You can get my item rack cheap if you want.

Sent from my DROID RAZR HD using Tapatalk

Title: Re: Wireless from board to camera?
Post by: Jonathan Johnson on May 01, 2014, 06:01:28 pm
You might look into something like this:

http://en-us.sennheiser.com/wireless-clip-on-lavalier-microphone-set-presentation-ew-100-eng-g3

The above kit from Sennheiser includes a bodypack transmitter, a plug-on transmitter, and a camera-mount receiver.

You could run an AUX send through a DI box to the plug-on transmitter.

Sennheiser (and others) also makes transmitters for IEM systems. If these transmitters are compatible with the camera receivers, that option would also work.

I'm sure there are systems out there for this purpose; I'm too lazy to do your research for you. :-)
Title: Re: Wireless from board to camera?
Post by: g'bye, Dick Rees on May 01, 2014, 06:06:51 pm
Well folks,
Got a job where they want to videotape some acts on the stage.  I can set up an aux easily enough (pre fade, post eq) via XLR - done that before. - they want to go wireless.  I know something exists -
I'm guessing it would be similar to a wireless monitor feed - but different.


Any clues as to what the something and if it is something that can be rented?


frank

Frank...

Make a safety dub in anticipation of the inevitable glitches with untried systems interfacing with consumer level gear...
Title: Re: Wireless from board to camera?
Post by: Jonathan Johnson on May 01, 2014, 07:14:21 pm
Frank...

Make a safety dub in anticipation of the inevitable glitches with untried systems interfacing with consumer level gear...

This is a good plan, as it will provide a level of redundancy. However, be aware that this can represent a lot of work. If you're not using gear with a synchronized time source (word clock) for both audio and video recording, synchronizing the audio during post-production will make you go bald.
Title: Re: Wireless from board to camera?
Post by: Tim McCulloch on May 01, 2014, 07:24:38 pm
This is a good plan, as it will provide a level of redundancy. However, be aware that this can represent a lot of work. If you're not using gear with a synchronized time source (word clock) for both audio and video recording, synchronizing the audio during post-production will make you go bald.

Follicularly challenged. ;)
Title: Re: Wireless from board to camera?
Post by: Jerome Malsack on May 01, 2014, 07:47:34 pm
That would depend on the Video camera being used.  Might not support two channels.  If sending the smpte
Then he may have to send single time code and then place the stereo audio ontop. 

Title: Re: Wireless from board to camera?
Post by: frank kayser on May 01, 2014, 10:47:07 pm
Thanks, folks.  During some of my additional research, a couple things, echoed here, became clear.
- Make a separate "safety" recording and sync later - the inevitable drop-outs.
- Stay away from wireless if at all possible.


Most of the other video sites I visited were so intent on the above points, absolutely nothing was said about equipment or line/mic levels or whether IEM was usable.


I did not see anything about the sync/word clock issue in my research - I would suspect that could be quite the problem.  The video producer's problem.


I did look at the Senn ENG systems, and I'm sure the answer was there but not knowing enough about what the transmitters were expecting and what the receiver outputs - had a hard time putting 2 and 2 together.


I've fed this camera (one of those community TV studios) with a line-level aux via XLR straight into the camera.


So, I may have enough info - a lot more than I had. 
Thanks!


frank
Title: Re: Wireless from board to camera?
Post by: Mike Pyle on May 02, 2014, 01:36:59 am
I use a Sennheiser bodypack transmitter fitted with XLR input cable, and adjust the pack sensitivity to prevent clipping. Then I provide the video crew either a standard half-rack receiver or the bodypack camera receiver. Usually they have a mixer of some sort to plug this into, but on occasion have to adapt it directly to the camera. It's best if they do have a mixer, because they should also use an ambient mic to mix in the sound of the room and audience. If they don't, you might also want to set that up in your feed. A video recorded only with a dry mix from the board sounds dead.
Title: Re: Wireless from board to camera?
Post by: Jonathan Johnson on May 02, 2014, 01:47:06 am
Follicularly challenged. ;)

More like follicular trauma.

To give more detail about the word clock issue, it's this: without a common time reference, audio recorded using separate A/D converters will play back at slightly different rates when combined into a single medium. If audio is recorded separately from video, when combined together the audio will eventually drift behind or ahead of the video.

The reason is that no two A/D converters run at exactly the same rate. One may record at an average 44,090 Hz while another may record at 44,112 Hz (instead of the nominal 44,100 Hz). This is due to slight variations in the oscillation of the quartz crystal regulator based on temperature and other factors. If you have a common time source/word clock, then both A/D converters will use the same oscillator. With identical timing, you should be able to sync the audio to the video easily. (I don't know how or if word clock timestamps the data; if it does, it seems like it should be able to automatically synchronize audio and video.)

For short clips, the variation will be unnoticeable, but synchonizing the start of the clip can still be difficult. For longer clips -- say, 30 or 60 minutes -- the variation will become more noticeable the further along you are in video.
Title: Re: Wireless from board to camera?
Post by: g'bye, Dick Rees on May 02, 2014, 05:20:59 am
Thanks, folks.  During some of my additional research, a couple things, echoed here, became clear.
- Make a separate "safety" recording and sync later - the inevitable drop-outs.
- Stay away from wireless if at all possible.


Most of the other video sites I visited were so intent on the above points, absolutely nothing was said about equipment or line/mic levels or whether IEM was usable.


I did not see anything about the sync/word clock issue in my research - I would suspect that could be quite the problem.  The video producer's problem.


I did look at the Senn ENG systems, and I'm sure the answer was there but not knowing enough about what the transmitters were expecting and what the receiver outputs - had a hard time putting 2 and 2 together.


I've fed this camera (one of those community TV studios) with a line-level aux via XLR straight into the camera.


So, I may have enough info - a lot more than I had. 
Thanks!


frank

Oh, it can be done wirelessly.  Lectrosonics make great gear for this...but you have to be willing to pay the price.  I feed wirelessly several times a year, but it's the cameramans Lecro rig.  Otherwise I always have an emergency backup recorded to a Marantz machine...also the property of the camera crew.  We used to use Cd, but the 80 minute limit made it touchy.

The video guy doesn't mind fixing it and re-synching every few minutes if it saves the job.  Getting backup recording with time code is too expensive for us.  The cost of the Lectrosonics camera rig is easily defrayed over a years gigs while spending that same money on something that only comes into play once in a blue moon is less justifiable.

It's their decision here.  Go with it, pass on any increased cost to them and let them know the consequences inherent in working with non-coded audio. 

Any problems are theirs.

Title: Re: Wireless from board to camera?
Post by: Jerome Malsack on May 02, 2014, 04:58:33 pm
You can also consider using a click track for your timing signal.  Not as fancy as the SMPTE or other automated systems. 
But it will have the ability to remove with an out of polarity track.  Also you will be keeping things in ball park on timing.

Title: Re: Wireless from board to camera?
Post by: kel mcguire on May 02, 2014, 05:56:56 pm

some clarifications:

You don't need W/C to accurately sync up video to audio. Except for Field recorders such as Zaxcom or Sound Devices, most recorders don't have W/C anyhow. Timecode is often sent to and from cameras and recorders. that makes it easier to spot areas needed in post and line stuff up.

music is easy to sync up in post. Often you don't have the ability to slate the cameras and recorder but there are some many percussive elements it's pretty easy.

The drift between devices is because of the crystal clocking. For music it's of little worry since things come in 3-6 minute chunks, unless it's orchestral. A nudge here and there, if even needed is all that's needed to fix. I made some tests of audio equipment i use for TV and concert production to check for clocking drift: Zoom h4n, H6, Protools, SoundD and Roland all running autonomously but recording the same signal at the same time. After 45 minutes the recorders were pretty much all within 2 frames of each other.

The "butt plug" transmitters can work just fine. Typically cameras receive a "hop" from the audio mixer and have receivers set to same frequency.

I've done many music/concert shoots where the cameras just used their onboard mics and the audio was replaced later. If they happen to want to edit and just use the camera sound then you'd have to nail it pretty well and hope for a clean RF.

a redundant recorder, like a Zoom sure gives some piece of mind.

You can get some splitters and do your own thing too.




are the cameras going to a truck or switcher? how many cameras?
how are you distributing the audio to all the cameras?
is there no snake connecting FOH with the stage?
Title: Re: Wireless from board to camera?
Post by: brian maddox on May 03, 2014, 11:39:15 am
some clarifications:

You don't need W/C to accurately sync up video to audio. Except for Field recorders such as Zaxcom or Sound Devices, most recorders don't have W/C anyhow. Timecode is often sent to and from cameras and recorders. that makes it easier to spot areas needed in post and line stuff up.

music is easy to sync up in post. Often you don't have the ability to slate the cameras and recorder but there are some many percussive elements it's pretty easy.

The drift between devices is because of the crystal clocking. For music it's of little worry since things come in 3-6 minute chunks, unless it's orchestral. A nudge here and there, if even needed is all that's needed to fix. I made some tests of audio equipment i use for TV and concert production to check for clocking drift: Zoom h4n, H6, Protools, SoundD and Roland all running autonomously but recording the same signal at the same time. After 45 minutes the recorders were pretty much all within 2 frames of each other.

The "butt plug" transmitters can work just fine. Typically cameras receive a "hop" from the audio mixer and have receivers set to same frequency.

I've done many music/concert shoots where the cameras just used their onboard mics and the audio was replaced later. If they happen to want to edit and just use the camera sound then you'd have to nail it pretty well and hope for a clean RF.

a redundant recorder, like a Zoom sure gives some piece of mind.



Just add my two cents worth on the whole re-syncing everything up later thing. Modern nonlinear editors make this process so ridiculously easy that it's not even something you need to worry about anymore. The latest version of Final Cut Pro actually does it automatically. So while it used to be true that you had to be very careful about timecode and things like that, those days are largely ancient history. So long as all of the video has some sort of audio on it, even if it's just the onboard microphone, that video can be synced to any other audio recording very very easily.
Title: Re: Wireless from board to camera?
Post by: Karen Furno on May 09, 2014, 08:56:28 pm
You might look into something like this:

http://en-us.sennheiser.com/wireless-clip-on-lavalier-microphone-set-presentation-ew-100-eng-g3

The above kit from Sennheiser includes a bodypack transmitter, a plug-on transmitter, and a camera-mount receiver.

You could run an AUX send through a DI box to the plug-on transmitter.

Sennheiser (and others) also makes transmitters for IEM systems. If these transmitters are compatible with the camera receivers, that option would also work.

I'm sure there are systems out there for this purpose; I'm too lazy to do your research for you. :-)
This Sennheiser kit rocks.  I've had pro camera and TV people plug into my XLR line out or the mic level pressbox while their receiver jacks right into their camera.  I like the kit so much, I bought my own.  The transmitter and receiver have tons of gain range from line level to mic level in their settings.  The transmitter will plug into the end of any old wired mic and turn it into a wireless unit.