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Shotgun Mics and XLR adapters

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Erik1185
Shotgun Mics and XLR adapters
on Jun 24, 2007 at 8:52:49 pm

What is a good inexpensive shotgun microphone that uses XLR inputs?

Also, are there any negative issues with using an XLR adapter like this one?

http://www.bhphotovideo.com/c/product/423360-REG/Hosa_MIT156_MIT_156_Low_to...

Thanks in advance.


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cow
Ray Palmer
Re: Shotgun Mics and XLR adapters
on Jun 24, 2007 at 9:01:26 pm

Are you familiar with phantom power? Most quality shot gun mics will either require phantom power from the camera or will use a built in battery in the mic itself.
I have never seen phantom power supplied from a camera via the 1/8" mini but it might exist.

That is why some Beachtek adapters will provide the XLR to mini adapter plus it also can provide phantom power.


Ray Palmer, Engineer
Salt River Project
Phoenix, AZ
602-236-8224 office
There are three types of people in this world, those that can count and those that can't.


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Rodney M
Re: Shotgun Mics and XLR adapters
on Jun 25, 2007 at 2:18:51 am

Ray is correct if you are going to use phantom power to power the mic. That cable wouldn't work. However, you are going to be looking at affordable shotgun mics. Probably an electret condenser shotgun, which most often can be powered by an internal battery. If you do get one of these types of mics, then this cable will be fine. Make sure you get an impedence matching cable (which the one you linked to is). Also, some mixers have a dedicated 1/8" output specifically designed (impedence matched) to interface with consumer cameras.

Check out the Rode NTG-2. $300, short shotgun, internal battery powered. If it's as good as some other Rode mics, then it should be fine.



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edward  chick
Re: Shotgun Mics and XLR adapters
on Jun 26, 2007 at 2:53:23 am

Also look into the Sennheiser ME66 with the K6 power module. It can be powered via a AA batt or phantom power.

ed


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Ty Ford
Re: Shotgun Mics and XLR adapters
on Jun 26, 2007 at 10:53:42 am

Rodney,

You do NOT need an impedance matching cable.

Ty Ford

Ty Ford's "Audio Bootcamp Field Guide" was written for video people who want better audio. Find out more at http://home.comcast.net/~tyreeford/AudioBootcamp.html
or http://www.tyford.com
Download Ty Ford's "Existential Boogie" from iTunes now.


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Rodney M
Re: Shotgun Mics and XLR adapters
on Jun 26, 2007 at 2:10:34 pm

As Ty so elequently stated ;-) impedence matching isn't necessary here. It is not necessary, in fact it could be degrading, to impedence match a low impedence output to a high impedence input. There is no loading between the two.

I'll be in the corner with my tail between my legs.





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Erik1185
Re: Shotgun Mics and XLR adapters
on Jun 26, 2007 at 8:37:52 pm

Thanks for the help!


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Ty Ford
Re: Shotgun Mics and XLR adapters
on Jun 27, 2007 at 11:40:11 am

Rodney, Ed, Erik, et al

A couple of things about mic to camera cables.

If you don't have XLR inputs on your camera, 99% of the time that mini jack on your camera will be a stereo mini jack.

Basic Fact: Plugging a mono mic into a stereo jack doesn't work.

Solution: Although a good mixer like the Sound Devices 302 would be my choice here. You can make it work with an adapter cable unless the mic requires Phantom Power.

You do not need a cable/adapter that changes impedance. The impedance of mics matches just fine to these camera inputs. "Matching", by the way, does not mean having the mic impedance match the camera input impedance. It is quite normal for there to have a 50 Ohm impedance mic feed a 2k Ohm or higher camera impedance input.

The reason the impedance adapter devices have received attention is that some have the right physical connections. Some don't. More below.

If Phantom Power is not an issue, there is one other issue. Some camcorders provide a low voltage to power certain electret mics and other things. This voltage can mess with any other mic you attach, compromising the audio. So, in this case, you need something to stop this voltage from getting to the camera.

The simple converter cable (female XLR to male mini TRS) will not work in this situation because you have mono source feeding a stereo input. HOWEVER, if the plugs are wired differently, it will work. To do that, pin #2 of the mic must connect with BOTH the tip and ring of the mini TRS plug on the other end of the cable. That way the mic audio feeds both left and right camera inputs.

There are cables wired that way, but not all of them have a small voltage blocking capacitor that blocks the camera voltage from getting into the mic. If your camcorder doesn't generate the voltage at its mini TRS input, you may find a properly wired cable without the capacitor, BUT a standard female XLR to mini TRS male WILL NOT WORK. Only one that's wired for mono to stereo will.

Here's a link to Trew Audio's solution. There are two cables. One for using one XLR mic. One for using two XLR mics. (You can not use Phantom Powered mics with these cables).

http://www.trewaudio.com/store/home.php?cat=21

Let's be safe out there.

Regards,

Ty Ford



Ty Ford's "Audio Bootcamp Field Guide" was written for video people who want better audio. Find out more at http://home.comcast.net/~tyreeford/AudioBootcamp.html
or http://www.tyford.com
Download Ty Ford's "Existential Boogie" from iTunes now.


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Rodney M
Re: Shotgun Mics and XLR adapters
on Jun 27, 2007 at 2:49:51 pm

Ty, thank you for the thoughtful and informative post. My carelessness is shaming at the moment. I evidently had a very large brain fart. In my mind I was thinking he was taking an XLR feed into a MONO 1/8" plug (mono mic in). Even though the link clearly states that the cable is an XLR to a TRS 1/8" and even though I said "yes that cable will work", obviously it will not. I'm well aware that you can't feed a mono mic feed into a stereo plug without some rewiring. I'm not sure where the disconnect happened in my mind. It was an honest mistake. A stupid, but honest, mistake. My apologies to all. I guess it really is time to start taking those omega-3, fish oil pills.

Secondly, I was just absolutely wrong about the impedance matching thing. I'm not sure why I thought you needed to impedance match a low impedance output to a high impedance input. No excuses, I was wrong. Now I know.

It's obvious why Ty is a moderator.





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Ty Ford
Re: Shotgun Mics and XLR adapters
on Jun 28, 2007 at 10:50:48 pm

Dear Rodney,

Your humility is only exceeded by your graciousness.

Here's the thumb rule for impedance.

Low to high; good. High to low; bad.

Think of a 3" fire hose being capped off to feed a 1" hose. The LOW impedance of the 3" hose feeds the HIGH impedance of the 1" hose. That works.

Turn it around. The 1" hose feeding the 3" hose. That's high into low. That doesn't work.

Does that help? :)

Regards,

Ty



Ty Ford's "Audio Bootcamp Field Guide" was written for video people who want better audio. Find out more at http://home.comcast.net/~tyreeford/AudioBootcamp.html
or http://www.tyford.com
Download Ty Ford's "Existential Boogie" from iTunes now.


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david conrad
Re: Shotgun Mics and XLR adapters
on Mar 15, 2013 at 7:11:31 pm

My question concerns a similar connection concern. I want to connect the output of a Microphone pream XLR balanced to the 3.5 mm audio input on a imac G5. The jack requires line level as it provides no voltage itself. I've read that it accepts mono or stereo. What would be the best way to wire the XLR to a 3.5 mm trs or ts?


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Erik1185
Re: Shotgun Mics and XLR adapters
on Jul 2, 2007 at 5:58:04 pm

Ty,

Thanks for the information. I tried this adapter out --

http://www.bhphotovideo.com/c/product/352326-REG/Audio_Technica_AT8341_XLR_...

-- with the Rode NTG-2 and received a very low signal. Is the solution to this problem buying the cable with the DC voltage blocker?

http://www.trewaudio.com/store/product.php?productid=146&cat=21&page=1

Thank you.



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Erik1185
Re: Shotgun Mics and XLR adapters
on Jul 3, 2007 at 12:48:23 am

I should add to my previous post that when I say I recieved a very low signal I mean the amplitude is very low and there is a significant lack of low frequeinces.

I also tried using an XLR cable with an old XLR to 1/4 adapter and from there went to a 1/8 adapter. The result was a strong signal with all frequencies present (alas, sound was only present in one channel).

This is the XLR adapter that I used in this test.

Why did the Radioshack XLR adapter combined with the additional 1/8 adapter produce near sufficient results and the original XLR to 1/8 cable detriment the signal?



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Rodney M
Re: Shotgun Mics and XLR adapters
on Jul 4, 2007 at 4:55:27 pm

Which camera/device are you plugging into? What does it say above the jack? It sounds to me that you are plugging into a mono mic input, which would need a mono 1/8" plug.



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Erik1185
Re: Shotgun Mics and XLR adapters
on Jul 4, 2007 at 5:46:53 pm

Panasonic PV-GS70. Above the jack it says "Remote/Mic (Plug In Power)"


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Erik1185
Re: Shotgun Mics and XLR adapters
on Jul 5, 2007 at 1:31:24 am

I was recommended this cable today.

http://www.shure.com/ProAudio/Products/Accessories/us_pro_A96F_content

It looks like it should do the job...

Any thoughts?

Thanks again.


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Rodney M
Re: Shotgun Mics and XLR adapters
on Jul 5, 2007 at 11:52:31 pm

Well Erik I just downloaded the manual on the PV-GS70 and it appears that the mic/remote jack does indeed use a stereo mini jack. However, this input was designed for use with the remote control/narration mic combo. So I'm guessing that the remote function is wired perhaps to the ring portion of the TRS plug, while audio is on the tip (sleeve being the ground). You might need to wire a female XLR to male TRS in this manner:

XLR Pin 1 to 1/8" Sleeve.
XLR Pins 2&3 to 1/8" Tip.
Nothing is wired to the 1/8" Ring.

You may still need the voltage blocker.

Ty, would you please check this?



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Junaid Syed
Re: Shotgun Mics and XLR adapters
on Nov 20, 2010 at 6:37:21 am

What value should I use for the capacitor? I saw the link:
http://www.rcrowley.com/CamAdapt.htm
Is it OK?


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