Phantom Power
 

What in the world is Phantom Power? How can the XLR mikes be powered by Phantom Power?
I am not clear on this. I am sorry to probably ask a dumb question.....

A sound expert could probably answer this much better, but some microphones require phantom power to operate. Correct me if I'm wrong, but I think it's because they don't have enough power by themselves to fully function, so they require addition power to work correctly.

Each microphone varies on this however, and it can be dangerous to have phantom power on with a mic that doesn't need it. So only turn this option on if you are 100% certain that the microphone you are using requires it.

Howdy Ed,

Not a "dumb" question...it was only a short time ago that I didn't have any idea, either, and that's what DVinfo is all about! I have a TON yet to learn, but each day that I log on here I chip away at the very long list of "stuff I don't know!"

Brent nailed the essence of it, but here's a link to an informational page at the Audio Technica web site that I found to be a really helpful, quick, and easy read:

http://www.audiotechnica.com/using/m...ide/index.html

Definitely true that you need to be very careful to have the XL2's Phantom Power switch OFF unless you mean to have it on. Canon explicitly warns you can damage stuff otherwise.

Hello Ed,

I was a professional sound engineer for about fifteen years before moving to video production. Here's the deal with Phantom...

There are basically 2 kinds of microphones: Condenser and Dynamic (there is technically a third: ribbon. But they are so rare and, as far as I know, never used in video, and irrelevant to this discussion)

Dynamic microphones do not need phantom power. Condenser mics do. There are fantistic types of both mics. One is not better than the other - they have different functions.

In a dynamic microphone, the diaphragm of the mic (the membrane that vibrates when sound comes in) is connected to a piece of metal inside a magnet. As the diaphragm vibrates, the metal moves next to the magnet and electric current is formed which is transferred as voltage down the wire. It's like a speaker in reverse. The magnet and metal are capable of creating their own current, so they don't need an outside source of power.

In a condenser microphone, there is no magnet. The phantom power is fed up one of the 3 XLR pins and creates a small electronic field inside the microphone - like the spark on a spark plug, only it's not intermittent, it's constant. As the diaphragm moves, it causes fluctuations in this electronic field. The fluctuations are transmitted as voltage down the wire.

As a general rule, condenser mics are more sensitive and able to pic up sound a greater distances. They also tend to be more delicate and more expensive. Most overhead type mics are condenser. This is a generalization, you will find exeptions.

Dynamic mics are more rugged and can handle greater sound pressure levels. They tend to be less expensive and warmer sounding. Most popular hand-held mics are dynamic. Again, this is a generalization. There are certain exceptions to everything in the world.

Hope this helps,

Vence Vida
Creative Juices Video

Just as a bit of clarification: The metal I refer to is actually a coil that the magnet moves through, which is why dynamic mics are also called moving coil microphones.

-Vence Vida
Creative Juices Video

Hi Vence,

Welcome to DV-INFo. Thanks for your helpful response. I just wanted to expand on your post a little bit for Ed's sake.

Some condenser mics can have their power supplied by an internal battery thus not requiring phantom power. Some of them are smart enough to switch off the battery and use phantom power if it's detected by the mic.. Some use battery only( I have an old Radio Shack wired lapel mic in this category).

Ed, as Vence stated, you need to understand what type of power your condesner mic needs, and only turn on the XL-2 phantom power if necessary.

-gb-

Great stuff. Thanks guys. Now I understand. Where do you get this kind of info unless you read these threads. I am overwhelmed by the knowledge base.
So, What about wireless mikes? What kind are they? I presume Dynamic...Correct?

Also, is there any danger, electrically that might damage my XL2 in using a condenser mike and turning on the XL2 phantom power switch?

Quite honestly, I don't believe there are any shortcuts to learning videocraft. I've done lots of posting, lots of other reading, and lots of experimenting with my gear and after two years, I'm still in the amateur league.

I've only used my own Senn G2 ENG kit, but I'd guess that most if not all wireless lav systems are set up similarly. Since the receiver unit has its own battery power supply, there is no need for phantom power. For a condensor mic -- which would require power, either a battery or phantom -- turning on phantom power is needed to run the mic and of course won't damage it. For any given hardware, as mundane as it may sound, you just gotta read the manufacturer's instructions. There's lots of different hardware configs out there.