Recording Sound off the P.A.
Has anyone had success getting an audio feed off the P.A. and running it directly into the camera. What are the pitfalls? Is it possible to plug a wireless mic transmitter into a P.A. and run it wirelessly into the camera. I have tried this but experienced problems with distortion. I think it is to do with running a line source into a mic. I think I need some sort of attenuator. It would be great to hear from people who have found a good way of doing this.
[klaus] "I have tried this but experienced problems with distortion. I think it is to do with running a line source into a mic. I think I need some sort of attenuator."
There's no doubt that connecting a LINE output into a MIC input is a very bad idea.
A "Line Level-to-Mic Level Attenuator" (aka a PAD) is just what you need under these conditions.
Here's a link to an ADJUSTABLE in-line pad that would be very helpful:
Of course, many audio boards have MIC LEVEL outputs available as well as LINE LEVEL so if you'd connect to the mic level outputs you would not need a pad.
If you're talking about connecting to an audio board that's being operated LIVE by a DJ or MC, then you'd be miles ahead if you can get the operator to help you connect and do a few LEVEL TESTS before everything starts for real.
Many times the operator can feed your wireless (or direct cable) by a mixer output that has its own individual level control.
If so, and the DJ doesn't mind, YOU (or the DJ) can go to the board and tweak that knob that's sending your feed and you can fine-tune it as the night goes on.
Yes, attenuators are what you're missing, also known as matching transformers. You can get them as small self-contained units that look like mic couplers, Shure makes a couple nice little ones, some switchable in level.
Typically PA systems and mixers don't have a lot of extra XLR outputs to feed you, and almost never a spare mic-level out, you usually have to settle for line level thru a phono jack or RCA jacks. Balanced audio all the way thru is what we prefer, and radio shack adapter voodoo at the back of the board may introduce sources for hum and the like. Something to watch out for.
In desperate situations, I have also gotten acceptible results putting a dynamic stick mic or even a wireless lav next to a PA speaker. Hey, they mic electric guitar speaker cabinets and the like, so it's not so weird, it's just not usually the best practice in video of events, because any buzz or hum in the PA gets magnified. If you place the mic far from the speaker, enough to reduce the buzz, you get audience talking leaking into the feed.
One other consideration is the difference between a "wet" and "dry" mix, and the difference in a mix made for PA versus one made for video. The mixer guy may have EQ and such tweaked to best deal with the room acoustics for the audience's ears, and that may not be the same as mixing for good video use.
You also need to worry about if you need audience response and ambience in the tracks somewhere... reactions to jokes, applause, etc. which the PA feed may or may not give you. Shotgun on a second channel on the camera may or may not be enough for that.
My preference is to run a hardwired stick mic to the podium and use good shielded cables all the way back to the camera. Everything else besides that is a compromise forced by the specific circumstances.
One final pitfall you may encounter is that the sound guy will screw ya!
Here is one particular thing to look out for. When you do your soundcheck before the event you will get a considerably different level than when the actual event starts. This is because they will almost always figure out that they need to crank up the volume once the event starts and they have a full room (as opposed to the empty room that they did the check with). In most cases this will result in your feed getting quite a bit hotter in the matter of a few seconds...you need to be prepared for it and make sure you leave lots of room to turn down. (Also, leave some room to turn up, too. You just never know with these guys!) In addition, they will continue to fuss with it throughout the night, so be prepared for your levels to dance around.
absloutley Alex - the other thing (if this is a band) is to make sure all the instruments are going through the PA. In smaller venues the drums might not