What the heck does this mean...

B

balrais1

Member
In keeping with buying a great mic I decided to rent out the AT 4073a and test it for myself. Everything was going fine until the person asked if my dvx100a is equipped with "PHANTOM POWER"...

Luckily for these forums I remember reading something about it and reluctantly said "Yes, it does." without knowing a lot about what it means.

Can someone please give me as much detail about phantom power, and what I need to know about setting up the AT mic properly? I also need to know the best possible way to config it and any tips or tricks you know.

Right now all I know about phantom power is that the mic will draw out power from the battery and the pan's range accepts from 9-52Hz. I'm still a newbie to all this. Your advice is appreciated.
 
The AT 4073A is phantom-power-only, so there's no setup. (Unless the AT brochure lied).

So...the instructions are: Plug the mic into the camera. Turn on the appropriate mic power switch (next to the channel select switches on the LCD side) for the mic channel being used.

:)
 
Phanton Power is what your AT 4073a will need in order for it to work. Once you have plugged your mic in (to either Mic Input 1 or 2, making sure those are switched to Mic and NOT Line) - Now open up the monitor and you will find some controls under there for Channels and Input. You will want to switch the CH1 SELECT switch to INPUT 1 (or INPUT 2 if you want the signal to be routed to INPUT 2) You can actually have the signal go to both Channels of the tape. More on this later. Lets stick to INPUT 1 for now. Now to the left of this is the MIC POWER +48V switches. Since your mic is plugged into INPUT 1, you'll want this switched to ON. This is your Phantom power.

Taken from WikiPedia:
Invented by Neumann microphones in 1966, Phantom power is a widely-used method for supplying current to devices over signalling cables, especially audio. This is most often used for condenser microphones, and occasionally microphones of other types.

Adjust your levels to a good level. From what I've learned from trial and error and from this wonderful site, getting a Level that is at its max, the 3rd red bar, nothing above that.

Now if you want both channels of your recording to get the signal (meaning CH1 and CH2 records audio to tape) Plug your mic into INPUT 2. Turn on Phantom Power for INPUT 2 (you can turn off the INPUT 1 Phantom Power). Then you have to switch both the CH 1 SELECT and CH 2 SELECT switches to INPUT 2. This tells the camera to route the signal of INPUT 2 to CH 1 and CH 2. WHY WOULD YOU WANT TO DO THIS? Well it's kind of for a safety reason. Doing this will give you a safe backup in POST. On the camera you would adjust CH 1 to a level that is just right (the red 3rd bar) and adjust CH 2 a bit lower than that. Just in case the levels get way too loud, you have a second track to choose from in post that didn't record so loud, that didn't get blasted out. This option is great for run-n-gun situations where you might not get a second chance to capture the audio. It's good to have options.

As far as other techniques, I would search the Audio Forums for more. But what I wrote above is what I use to get good useable audio with a "Camera Mounted" shot-gun mic.

Goodluck :beer:
 
Something you have to consider
AT 4073 is very hot ( loud in simple words) output mike which may cause your camera mike input distort badly when you record high level signals ( adjusting the potentiometer not to hit the last red wouldn't prevent already distorted signal).
i suggest that if you run that mike as camera mike make 15 db attenuation cable for camera connection and if you use it on boom you can buy attenuation in-line barrel adaptor at 8202( -10,-20,-30 db ) for proper use .
the mike can work with 9-52 volt range phantom source , that's extremely useful since not all mixers supply 48v like this camera .
it will drain about 1.5% of you battery capacity ( less then 2 minutes for each camera hour)

Dont forget to set the mike level on -50 db internal setting in the camera recording setup
 
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