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Need input on adapting XLR cable to shortgun mic for booming.

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Crye Biggie
Need input on adapting XLR cable to shortgun mic for booming.
on Jan 6, 2013 at 3:35:16 pm

I have a SONY NEX VG20 and Sony indirectly recommends ECM-CG50 Pro Shotgun Microphone in one of their handbooks. However, the cable for this is too short, and someone said the mic is designed to be camera-mounted (made for direct on-camera plugging for best results). He added that when a mic cable gets to the 10-15 feet or longer length, the cable can turn into an antenna that can pick up Radio Frequency Interference and Electro-Magnetic Interference (RFI & EMI)

ISSUE -- I would like to shoot short movies which will need Medium to Long shots, some in noisy environments, and so I need to boom the mic. I need a cable up to say 25ft long (I know I can use a Lav somehow)...

SHIELDING - As advised, I could get a 1/8" (3.5mm) male to 1/8" (3.5mm) female extension cable, but sources said it will most likely not be shielded (Lord, whatever that' too, means).

XLR -
Sources said the *best* option is to "get a shotgun mic which uses an XLR connector (I don't know if this means the admired ECM-CG50 doesn't/can't), connect it using XLR mic cabling to a XLR adapter (then he referred to "see juicedLink or BeachTek") - and the XLR adapter plus into the VG10". (well, mine is actually a VG20).

He rounded up that there are several options in between, but the goal is to use shielded cable for long cable runs; XLR mic cables are shielded/balanced.

---> My VG20 has an "external XLR adapter (sold separately).".

A complete noob on sound issues, I want to get the best I can. What's the implication/advantage of that info ("external XLR adapter")? I looked around all yesterday but it can be daunting to get what info you really need, given all the technical terminology and fact that responses may not necessarily refer to your model/brand/situation exactly. Since ECM CG50 is suggested by Sony itself, I trusted it [NOW BOUGHT] but I don't know how to use it with an XLR and as the cable is short. In simple terms, I can't tell from all the absorbed info if it is possible, and if possible, what is needed besides the mic, how to do the connection to get the best possible for the sacrifice.

Please any input will be so much appreciated, and alternatives (with similar cost) and/or general advise and considerations to get equipment which can help achieve my 'shooting distance' goal too!

Altitude is not all the problem. Taking steps is more of it.


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Brian Reynolds
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 6, 2013 at 10:13:04 pm

Have a read of this link it explains the difference between balanced v unbalanced connections. Then get back for further questions you might have.
http://soundinfo.wikidot.com/ballanced-vs-unballanced-audio


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Crye Biggie
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 7, 2013 at 4:29:48 am

Dear Brian, thanks for understanding and taking it from scratch. I read the article, pretty good, though hard to really grasp, with all the technical language. But I got the essence, and I decided it will be best to arm for BALANCED AUDIO, reason being I want to BOOM (Long cable) and shoot movies, not a home system.

My circumstances --

- My Mic (Sony ECM-CG50 Pro Shotgun Microphone) includes a shock mount microphone holder and shoe adapter (I trust you can figure from pic)

http://www.bhphotovideo.com/c/product/749831-REG/Sony_ECM_CG50BP_ECM_CG50_S...

Notice the cable supplied is SHORT, and see how its 'HEAD' (Pin) is ... and I hear it's 'Unbalanced'. Yet we want to run Long+Balanced.

- My camera (Song Nex Vg20) is...

http://store.sony.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10...

The problem is:
They say 'balanced' audio runs in XLR cables??. In that vein ...

- First I don't find it anywhere that the camera VG20 even accepts or works with an XLR adapter (they say VG30, a close upgrade, does).

- Second, an adapter such as the following is just too expensive, I can't afford right now...
http://www.sweetwater.com/store/detail/PCMD1XLR/?utm_source=Google&utm_medi...

So is it OK if I use long XLR cables with one like this...
https://www.google.com/#q=xlr+adapter&hl=en&newwindow=1&tbo=u&source=univ&t...

Sony has proven to have poor after sale correspondence, otherwise, how can't I know if the first consideration (VG20 accepting or not external xlr adapters or even how to GO ABOUT GETTING BALANCED AUDIO FOR BOOMING EXTERNAL MIC) ... So please consider that and don't feel bored.:D

Thanking again!

Altitude is not all the problem. Taking steps is more of it.


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Brian Reynolds
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 7, 2013 at 5:04:41 am

There are other brands of adapters that would work fine like 'BeachTek' or 'Juiced link'
The problem with an unbalanced cable is it might work fine 60% of the time but there will be other times it won't. And you will never know unless you monitor the output of the camera or when you get to play it back.... And by then it's often to late.
You maybe happy to accept the risk but as a person that makes a living from location sound I wouldn't touch an unbalanced extension mic cable with a barge pole.


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Crye Biggie
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 7, 2013 at 7:33:14 am

Thanks man. I guess there's no straight answer to this. So I'm just getting a normal 1/8" (3.5mm) cable. Tested 10m indoors and it wasn't that bad, but outdoors yet to be tested. Bless you and good luck! :D

Altitude is not all the problem. Taking steps is more of it.


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Peter Groom
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 7, 2013 at 10:55:52 am

That might not even work, although is highly risky.
The mic needs power which itll get from the camera. I doubt the voltage will survive a 10m cable and still be correct to drive the mic.

You MAY just have to accapt that the purchase was not right. The mic is designed for use ON the camera, where its power source is close.
Running unbalanced over a longer run will leave you open to Rf interference, which will vary depending on wherever you try to record. This is why pros use balanced xlr.

My suggestion would be to use a proper balanced XLR mic (with local power (ie an internal battery) and use a high quality starquad style screened cable. Then put that through a beachtek or similar device to convert down to your 3.5mm jack input, and that cable will only be very short hence minimising RF interference risk.
Peter

Post Production Dubbing Mixer


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Richard Crowley
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 7, 2013 at 3:21:13 pm

While I agree that Mr. Reynolds and Mr. Groom have given you excellent advice, I would encourage you go ahead and try using a SHIELDED 3.5mm extention cable. I have been doing this since I was a kid (in the 1970s) and the main downside is susceptibility to interference.

From years of first-hand experience, I can assure you that loss of "plug-in power" is NOT an issue with even with 100 feet or more of cable. The voltage is very low, and the current is also very low, which means that only the most flimsy and flaky of cables could have a potential issue with power.

The biggest concern with extending mini-phone mic connections is that the unbalanced connection is more susceptible to interference. It is imperative that you use an extension cable that is SHIELDED. This means that there is a layer of wire mesh surrounding the inner wires and that mesh (or wrap) protects the signal inside from much external interference.

Since earphones/earbuds use the same 3.5mm connectors, many (most?) 3.5mm extension cables are UN-shielded because earphone connections don't require shielding. I am noticing that because of the increased interest in connecting external mics to 3.5mm devices (camcorders and small digital audio recorders) there are now 3.5mm cables which state explicitly that they are shielded. I would not buy one that did NOT state explicitly that it is shielded. But then I have been making my own cables since I was a kid and I know what's inside. I have made several adapters that allow using real XLR cables with 3.5mm microphones to extend them successfully to 150 or even 200 feet.

But there are some kinds of interference that even the planet's best balanced, XLR shielded mic connections can't protect against. Cell phone interference is probably the worst. But fortunately, it is easy to manage by either having people shut off their devices or remove them several hundred feet away while shooting.

You haven't described WHAT you are shooting, so it is not possible to be any more specific in relating experience and expectations. For example shooting stand-up reporting with a lav clipped to the talent is going to be significantly different than trying to use your budget short shotgun mic cobbled onto a boom pole to pick up dialog in an action scene of a scripted drama with four speaking parts, etc.

As Mr. Reynolds observed, that XLR to mini adapter from Sony is vastly overpriced (as most of Sony's accessories are IMHO). I am a huge Sony fan-boy, but expensive is expensive and wise shopping can save 100s of $$.


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Ty Ford
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 7, 2013 at 1:26:13 pm

Hello Crye and welcome to the Cow Audio Forum.

You have been given good advice here by several of our seasoned regulars.

The main problem is that you bought a camera without professional (XLR) audio inputs. While it was a camera you could afford and offers a very good data rate for the price, they got the price down by skimping on many things, audio among them.

The $170 mic you chose has a hard wired plug on it. As you have found, this may prevent it from reliably being used with an extension.

(Please know that professional mics for this sort of work cost as much or more than your camera and are usually connected to a mixer that then feeds the camera or a separate audio recorder.)

My suggestion would be to try one of these: http://www.bhphotovideo.com/c/product/392841-REG/Rode_VC1_Stereo_Mini_Male_...

...and see if it works. No guarantee, but it's an inexpensive experiment with a piece from a company known for its problem solving. Ooops, you said 25 feet. So, guess not.

Next would be ditching the mic you bought and going with a self-powered professional shotgun or hyper and a cable that would allow it to be used properly with your consumer level audio input.

Something like this: http://www.trewaudio.com/store/DV-Cam-Mono-Input-Cable-CAMCX3F1-8.html?page...

This begs other questions; what do you intend to record and where? If you will be doing work inside most residential and office spaces, an interference tube based shotgun will perform poorly as compared to a hypercardioid mic.

And, given what you say you want to do, I think it that the best advice would be to dive in and learn about audio, get a separate recorder and match the audio to the video in your editing program, using the camera audio for rough reference. Movie making is not trivial and that why the popcorn costs so much! :)

Welcome to the wonderful world of sound!

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog:
Ty Ford's Blog


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Crye Biggie
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 12, 2013 at 5:20:13 am

Mighty thanks to you all, and Ty, I'm happy to be here...so active, just the right Audio place.
OK, being in China, it's kind of hard to explain what you want or find shops with professionals who would automatically doctor your problem as opposed to some employee who just sells stuff you name. They look into Sony's brochure and anything outside that, they say they don't know, don't want risks. My head was just getting blown up and I decided and got 10m of the normal 1/8" (3.5mm), and everything seems to work fine indoors. Looks like the one Ty suggested..

http://www.bhphotovideo.com/c/product/392841-REG/Rode_VC1_Stereo_Mini_Male_...

I'll go test outdoors tomorrow. Please input same on my next LAV post, if that's not too much asking.

Altitude is not all the problem. Taking steps is more of it.


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Ty Ford
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 12, 2013 at 1:54:30 pm

Great Crye,

Please let us know how that turns out!

"Please input same on my next LAV post, if that's not too much asking."
Sorry, I don't understand what you would like?

Regards,

Ty Ford
Cow Audio Forum Leader

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide
Ty Ford Blog: Ty Ford's Blog


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Crye Biggie
Re: Need input on adapting XLR cable to shortgun mic for booming.
on Jan 12, 2013 at 3:13:33 pm

Thank you, and ...My bad, Ty. I just meant I was going to make a post about LAVs (which I finally did), so was just using the chance to solicit more help in advance since my situation was already familiar for those who advised.

Thanks for your patience!

Altitude is not all the problem. Taking steps is more of it.


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