"Line" vs. "Mic" vs. "+48v": Countryman E6i w/Samson Airline at DVinfo.net

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Old May 8th, 2007, 10:06 AM   #1
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"Line" vs. "Mic" vs. "+48v": Countryman E6i w/Samson Airline

Our audio is not fancy: We use the tiny Samson "Airline" AL-1 wireless lav that transmits straight to a Samson "Airline" AM-1 receiver, and put that directly into our JVC GY-HD100UA and HD110U camcorders via XLR. We've shot a lot of videos this way and they sound fairly good, tho not great.

Now I have purchased a Countryman E6i head-mounted itty-bitty microphone. I put a micro-mini-plug on it so that it, too can use the AL-1 transmitter (which we love because it is so small and hide-able on our dancers and fitness performers). But the level coming into the camera is way lower using the E6i than via the AL-1's internal (or attached) microphone -- at least keeping the usual settings.

When I switch the Samson AM-1 receiver to "Line" however it sounds fairly good again. Yeah, there's a little hiss, however not more than I always get out of the Airline system.

Still I wonder about using a "Line" setting when it's a microphone that's plugged into the AL-1: Can that possibly be the right thing to do? Are there some mics that require a 'line-in' setting?

We have no one on staff who is really a sound recording expert (obviously!) -- I don't really understand the whole phantom power concept...so I'm looking for expert guidance. In my dreams I'm hoping for some advice that can boost the level of the E6i and get rid of the hiss while still allowing me to use the AL-1 transmitter.

So: What should be the correct combination of "Mic"-vs.-"Line" settings on the Samson AM-1 receiver plus "Line"-vs.-"mic"-vs.-"mic+48v" settings on the JVC camcorder?

How should these setting differ for the E6i compared to the AL-1's internal mic?

With thanks for your kind guidance,
Scott
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Old May 8th, 2007, 10:50 AM   #2
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48v phantom is used to directly power condenser microphone capsules, so it should only be used when a mic is wired directly to the input on the camera--and even then only if the mic in question is a condenser and requires phantom power. It would be a very bad idea to supply your wireless receiver with phantom power; you're likely to "fry" something. At best, even if no "frying" occurs, there's no way the current is ever going to make it to the mic itself, because there's no physical connection at all between the mic and the receiver. :)

A brief look at the powering requirements for the e6i reveals that the mic will accept a few varying voltages at correspondingly varying levels of impedence. My guess here--though I'm not familiar with your wireless system--is that the Samson's output voltage is something other than what the e6i needs in order to operate properly. My guess is that you're going to need some kind of in-line transformer in order to provide the correct current to the mic, though it's best if I let someone a little more familiar with these kinds of things give you a more definitive answer on that. You might even contact Countryman and see what they'd suggest; they might tell you you're screwed unless you buy a more expensive wireless system that will provide a current for the mic within the specified range, and they might be right unless you're willing to do a little research and build your own transformer. This is all purely guesswork and conjecture, though, so take it with a grain of salt. Someone else around here may or may not have better advice for you.

No matter what, though, you definitely do not want to use phantom power with your receiver. So at least I can definitively rule that out for you.
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Old May 8th, 2007, 12:20 PM   #3
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Quote:
Originally Posted by Jarrod Whaley View Post
...My guess here--though I'm not familiar with your wireless system--is that the Samson's output voltage is something other than what the e6i needs in order to operate properly...
You're really going to like the sound out of the e6i when you get it going right.

Countryman sells cable sets in numerous configurations. Go to countryman.com, click on the "Need a new cable?" link, and spec for your samson connector and order your cable. You don't need a new mic with this system, just the correct cable.

Overall, best signal to noise performance will come from getting your e6i wired correctly for the transmitter, setting transmitter gain correctly for the source, and for most camcorders, switching the receiver output to Line and the camera input to Line, adjust recording levels appropriately.

In other words, to get the best performance out of wireless, gain structure must be optimized at each point in the chain.

PS. Jarrod is exactly right in his comments about phantom - you don't want it for this setup. Yes, the transmitter will supply some power to the mic head, but this is on the order of 1.5 to 3v, and is usually called "plug in power" or "Mic power" to distinguish it from phantom. 48v phantom would fry the mic element (don't put an xlr plug on a countryman e6i cable).
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Old May 8th, 2007, 01:54 PM   #4
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Thanks, Jarrod and Seth!

Still eager to hear other views on this...in the meantime I seem to be 'getting it.' Hard tho it may be to believe, I've produced 40 DVDs without ever really zeroing in on my voice audio settings. I guess I was just lucky. Today for the first time I messed around with ALL the settings. And there are a lot of them!
-12 switch positions on the camera (plus 2 sliding gains)...
-6 choices in the camera audio menu...
-2 choices on the wireless receiver.
...144 potential combinations! HA!

Here's what I have come up with as optimal for the E6i in the JVC GYHD110 -- or at least as far as what seems to sound best in the headsets. I'm pleased to report, Seth that I DID have the correct cable, and (Jarrod) that I did NOT fry anything except myself, as I was sitting in the hot Manhattan midday sun as I did all this experimentation...

-ON the camcorder, I set the input for "mic" - (not mic+48v, just plain "mic")

-IN the camcorder audio menu set the "audio reference level" for "-20db" (not -12db)

-IN the camcorder audio menu set the "input reference level for "-60db" (not -50db)

-ON the microphone transmitter - well there isn't any setting there (so that one's easy!!)

-and ON the microphone wireless receiver, set it for "LINE" (not "Mic") - I'm still shocked to discover this!!

So the wireless receiver is set for "LINE" but that device is XLR'd straight into a camera channel that's set for "MIC" and together they are a happy couple. Does this make sense?

Regarding "mic+48v" -- there's none of it anywhere in this hook-up - altho I have also discovered that the mounted external mike on top of the camera (which we never use) likes the "mic+48v" setting: Nothing at all comes out of that mic without selecting "mic+48v" setting.

Seth you are correct that the E6i sounds superb! Today will go down in history as a great day for audio on bellydance videos!
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Last edited by Scott Shuster; May 8th, 2007 at 06:17 PM.
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Old May 8th, 2007, 07:01 PM   #5
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Sounds like you've got it working, Scott. Glad to hear it.
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Old May 8th, 2007, 07:29 PM   #6
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Well, I'm usually one to say "if it sounds good, it is good..." but, today must be my day off.

On page 9 of the Airline Micro manual available here:
http://www.samsontech.com/products/r...cro_manual.pdf

it shows a gain trim control next to the mute switch on the transmitter. On the top of page samson mentions turning up the gain until an appropriate level is heard on headphones plugged directly into the receiver.

Given that there is no indicator for gain on the transmitter, I'd put the mic on your instructor, have her speak loudly over the practice music, turn up the trans gain until it distorts and then back it off a little bit.

Then plug the receiver in to the camcorder, and see how the gain is working there, you might then have appropriate gain structure to try mic-mic, or line-line.

After all this BS oops I mean fine adjustments of gain structure, you should not only have the great sound of the e6i (I love that mic!), but also the best, most noise-free performance from your wireless.
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