Video Recording connections

[Robert F Jarvis]

Our theater want to stream a fund raiser. The Camcorder has a 3.5mm 3 pole TRS mic socket which is presumably for a stereo mic. Our Soundcraft EFX8 has a 3 pole balanced 1/4" Auxiliary balanced (I.E. mono) output jack. We normally send it to a amp/speaker monitor on stage. But for this show want to send it to the camcorder. Wondering how to get the mono balanced to the camera's LR input?

 

[jkowtko]

The video guy I work with has XLR inputs on his cameras so I have never had to deal with this on my side ... but a quick google search found the Saramonic SR-PAX1 ... I imagine there are others ...

 

[Robert F Jarvis]

Thanks. I will take alook

 

[Robert F Jarvis]

The answer (maybe to help others) seems to be to bridge one of the Balanced lines to the ground line and send this as ground to the mic input. The L and R inputs are then connected through separate 120 Ohm resistors to the other Balanced line.

 

[jkowtko]

I almost forgot ... if you are not concerned about the balanced signal you can wire 2 XLR female directly to the 3.5mm TRS ... here's what I made using a Hose CMP-159 and a couple of XLRF connectors, so I could record stereo on my Tascam DR100 digital recorder using Aux 5/6 outs from the board ... The Hosa CYX-405F should be the same as what I did ...

 

[Malabaristo]

If it's a short run, then you can get away with the purely wiring approach of adapting the two connectors as you found. If it's a longer run, then it would be nice to keep the signal balanced until you get to the camera. For that you would need an adapter with an impedance matching transformer (or "balun")... the ones I'm finding in a quick search tend to be XLR rather than 1/4" like this one: https://www.bhphotovideo.com/c/product/885062-REG/kopul_lmt_100_lo_to_hi_impedance.html

 

[Robert F Jarvis]

Looks about the simplest. I saw something similar only they jumpered the 'spare' line to the ground. And interestingly put a 120Ohm resister in series with the signal. My first thought was to bring the mono balance signal out on a 1/4" TRS from the AUX socket. It might be easier to the line outputs from the main channels (that normally go to the speakers). I'll get back to you on this I have a video conference busting in now.

 

[Robert F Jarvis]

If it's a short run, then you can get away with the purely wiring approach of adapting the two connectors as you found. If it's a longer run, then it would be nice to keep the signal balanced until you get to the camera. For that you would need an adapter with an impedance matching transformer (or "balun")... the ones I'm finding in a quick search tend to be XLR rather than 1/4" like this one: https://www.bhphotovideo.com/c/product/885062-REG/kopul_lmt_100_lo_to_hi_impedance.html

This is going to be a real short run. About 4' or 5'. I'll hold on to the other info for when I have to run a longer seed. Thanks

 

[macsound]

I'd recommend something like the Saramonic mentioned above or something like this. https://www.bhphotovideo.com/c/prod...kflex_ad2_single_channel_audio_mixer_for.html

Input levels are usually very finicky on cameras and having a dedicated volume control is nice. Personally my Canon 80D has terrible internal noise when the input is turned up past 25%, so it wants to see a super hot signal. But on another camcorder at a school, it wanted a very quiet signal.

 

[Malabaristo]

Input levels are usually very finicky on cameras and having a dedicated volume control is nice. Personally my Canon 80D has terrible internal noise when the input is turned up past 25%, so it wants to see a super hot signal. But on another camcorder at a school, it wanted a very quiet signal.

This is a very good point. I was thinking in terms of being able to control levels from the main mixer, but the camera person doesn't always have that luxury.

 

[jad17555]

What are you streaming with? If you are using a computer, a better solution is to use a USB interface or two to bring the audio and video into the computer and mix it there for the livestream.

 

[josh88]

Also maybe it shouldn't bear mentioning, but be wary of rights. Make sure what you want to do has streaming rights, if its a showcase make sure you get rights to each song, we're dealing with BMI right now because we'd need addendums to our contract if we used music for live streams. Its free on facebook because they have a license, its a different price if we charge for tickets versus take donations, and we're need to write a different contract if we stream on vimeo or a different video player. It's a mess.

 

[FMEng]

A few cameras can switch their input level to line, but most are only mic level inputs. Connecting the mixer output directly to a mic level input is either going to result in excessive noise or distortion. It would be better to put a 30-40 dB pad between the two. The Saramonic takes care of that, otherwise, the DIY project gets a little more complicated to do so that it works really well.

 

[almorton]

Isn't that what a DI box is for? Taking a line input and converting it to go down a balanced mic input.

 

[Ben Stiegler]

Isn't that what a DI box is for? Taking a line input and converting it to go down a balanced mic input.

yes, but his camera doesn't have balanced mic inputs - its unbalanced stereo (L/R/Gnd). Could just mix the whole show in mono, maybe?

 

[almorton]

Ah, ok, yes, if no balanced input then just a pad is needed
.

 

[RonHebbard]

Ah, ok, yes, if no balanced input then just a pad is needed
.

If you try to run the balanced mono output of a DI into his unbalanced stereo microphone input, wouldn't cancellation of bass, vocals, and other things panned down the center become a consideration, similar to value engineered vocal eliminators sold for the karaoke market? I've heard the vocals cancel but their stereo reverb returns are eerily left behind.
Toodleoo!
Ron Hebbard

 

[almorton]

Don't those vocal removers work by subtracting left from right to create a mono signal, rather than by summing?

 

[FMEng]

There are only two ways to do this properly. One is to solder up a purpose built cable with a built-in attenuator, and the other is to buy a product designed for the job. A kluge of adapters is unlikely to work correctly because there are multiple issues to deal with, balanced to un-balanced, mono to stereo, and line level to mic level. It isn't hard to find church videos on Youtube with all manner of audio problems caused by this very problem.

If the OP wants a cheap, solder together solution, I can draw it up and post it.

 

[TimMc]

Somewhere in the cobwebs of my mind, I thought Radial made a "reverse" Stagebug 5. Transformer isolated input, switchable pad, 3.5mm TRS stereo unbalanced output... but I'm not finding it at Radial... or Rapco Horizon ProCo... or RedCo.