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Old August 2nd, 2004, 08:36 AM   #1
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Multiple Mic's.....? How do i...

My Question:
I have a Canon GL2, how do I get sound in my camera with say 2 different mic's at the same time?

Like alot of TV shows, IE: Trading Spaces, etc, etc. They have a group of 3-5 people all talking with lav mic's on. How do they get all of em to go into the cam? A on cam mixing device? I dont seem to find them anywhere. I usually see the sound guy have a pack on with all these antennas sticking out of it, is he controlling all of them? But I dont have a extra guy to do this.

I want to use a Lav mic, and also a shotgun mic at the same time, How do I go about doing this? Can anyone show me an example of a product?

I have an Azden 3.5mm mini jack shotgunon my GL2, and a wireless lav mic.
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Old August 2nd, 2004, 10:19 AM   #2
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Hey Kevin, I have this same setup here http://www.droptodesign.com/test/camera/

I use a Beachtek DXA-4p with a shotgun and a lav mic. The mix is a multitude of the beachtek adapter, and the onboard controls on the camera. So far my tests have been very good on this. If you search my posts, you'll find the entire listing of my camera setup. I hope this helps.
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Old August 2nd, 2004, 10:59 AM   #3
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Nice setup,
But 1 thing, you mix the two mics with the beachtec adaptor? So I can have a person on a wireless mic, and also use a boom mic, and catch these 2 peoples voices on the cam, at the same time. Ok I think i get it the beachtex has 2 XLR Adaptors so i can plug both in and its basically a mixer as well, not just a adaptor to use XLR on the GL2? Am I correct? I was stuck on it just being an adaptor to use XLR
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Old August 2nd, 2004, 11:49 AM   #4
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Well, according to my experience and tests, you can plug the wireless mic into either the auxilary input or one of the xlr plugs. Then you can plug the shotgun into the other one. And one setting will give you the shotgun audio on the left channel and the wirless on the right channel. The DXA-4p does have a mono and a stereo setting which gives you more flexibility. And yes, the volume knobs on the Beachtek gives you control over the mix from each microphone, although you will still need to pay attention to what your audio settings are on the camera itself.
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Old August 2nd, 2004, 11:52 AM   #5
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The BeachTek boxes aren't really mixers in the true sense, even though they can "mix" the two mics together. It's more accurate to say that they have routing capability.
Except for the DXA-8, all the BeachTek type boxes are passive devices. Therefore all you can do is attenuate the signals from mics or line feeds, you can't boost them.
Most of these boxes have a switch labelled "MONO/STEREO". This switch keeps the two mic inputs separated in STEREO or it mixes both inputs to both outputs in the MONO position. For example there's no way to keep one mic by itself on one channel and get a mix of the two mics on the other channel using just the BeachTek.
Most of the time the MONO position is used to split a single mic to both camera inputs.
Most of these boxes also have an AUX mini jack input that is tied in with one of the balanced inputs. It varies from maker to maker how this linkage is wired and how you can use the inputs together or not depending on how the incoming signals are wired.
I realize this has been kind of a scattered response. If you have further questions just ask, one of us will be happy to answer.
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Old August 3rd, 2004, 08:52 AM   #6
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Thanks guys for your input. Very Helpful :-)
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Old July 30th, 2007, 04:17 PM   #7
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Same situation

First of all, Kevin, the subject line of your post was EXACTLY what was going through my head. Multiple mics...one camera...eyes cross...

Thanks to everyone for your input so far. My situation is this: shooting this weekend in a studio, with the Canon GL2. Want to use two wireless mics as I'm doing interviews with pairs of people. Currently have one Sennheiser G2 wireless lav mic at my disposal, and will probably rent a second one.

Three questions.

First: regarding the adapter boxes, any BeachTek model or the Canon MA-300, are those rent-able? Or will I need to buy?

Second: I've read some threads on the pros and cons of various boxes. Is there one that's better-suited for my particular camera, or does it just come down to preference & budget?

Third: I don't actually need the XLR inputs, since the wireless mics have cables that work with the 1/8" jacks. I just need a way to capture sound from two microphones. Is there a box that simply has a second 1/8" jack?

(Or is there a measurable benefit to using the XLR ports instead?)

Thanks for your help.

Sara
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Old July 30th, 2007, 10:12 PM   #8
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First of all, Kevin, the subject line of your post was EXACTLY what was going through my head. Multiple mics...one camera...eyes cross...

Thanks to everyone for your input so far. My situation is this: shooting this weekend in a studio, with the Canon GL2. Want to use two wireless mics as I'm doing interviews with pairs of people. Currently have one Sennheiser G2 wireless lav mic at my disposal, and will probably rent a second one.

Three questions.

First: regarding the adapter boxes, any BeachTek model or the Canon MA-300, are those rent-able? Or will I need to buy?

Second: I've read some threads on the pros and cons of various boxes. Is there one that's better-suited for my particular camera, or does it just come down to preference & budget?

Third: I don't actually need the XLR inputs, since the wireless mics have cables that work with the 1/8" jacks. I just need a way to capture sound from two microphones. Is there a box that simply has a second 1/8" jack?

(Or is there a measurable benefit to using the XLR ports instead?)

Thanks for your help.

Sara[/QUOTE]




Hi Sara!

If you look carefully at the date stamp at the upper left of the posts, you'll see this was a discussion from a few years ago. But don't fret - audio issues are eternal!

As to your questions, here are some ideas....

The Beachtek level stuff is on the inexpensive side of video gear, so most rental houses probably won't stock them because most people who need them just buy them. What any video rental house SHOULD stock and rent are real typical small pro audio mixers like the small Mackies, or the more video specific units like those from Shure, Cooper, or Sound Devices. The advantage, as someone else noted, is that they're ACTIVE so you get the ability to BOOST audio levels, as well as lower them. Often very useful.

Q2 - since your mic packs have unbalanced mic level audio outputs in the form of a small stereo mini-plugs - they're only suitable for feeding a single input. Physically "mixing" two outputs into a single input with "Y" cables or connectors is asking for phase and signal level problems.

Q3 - Sound aware folk will tell you that working with unbalanced audio lines like those you're talking about (lines terminating in mini-plugs) is something to be avoided whenever possible. Mic signals are VERY tiny voltages and as such are VERY susceptable to electronic noise and other problems. The cables essentially act like antennas for radio frequency energy/noise. TWO cables essentially doubles the antenna array for such noise! XLR cables are wired using a balanced line configuration to REJECT such noise.

Since it's not the preferred way to transport audio information, there's probably nobody who makes a "1/8th in mini plug mixer" because it's just not a good idea.

The preferred process with multiple Mics is to run balanced cable from the mics back to a mixer. Then a short run from that mixer to an interface device like the Beachtek - then a VERY short unbalanced line to the camera input.

That's the only dependable pathway to better quality audio.

Hope this helps - and...

Good luck!
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Old July 30th, 2007, 10:48 PM   #9
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Bill,

Thanks for your patient explanation of the various types of gear for this situation.

I had a feeling the Y-connector was a bad idea. Thanks for clearing up why. The last time I was at the studio, we tested out the wireless mic (using its 1/8" plug) and there was a distinct hum/buzz sound in the headphones.

It sounds like I could rent a mixer, although I'm a bit intimidated and I won't have anyone there to help me if anything goes wrong. I want great sound, but I'm willing to settle for the best sound that I can confidently manage.

The mic packs are both Sennheiser G2 evolutions. They come with both mini and XLR cables. Assuming that I don't rent a mixer, but I do buy an interface device such as the Canon MA-300 or the BeachTek DXA-4P, will it work to plug one mic receiver into one XLR input, and the other into the other? This is starting to seem like the most realistic course of action.

And if this is the plan, anything to watch out for?

Thanks again,

Sara

PS - date stamp. Got it.
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Old July 31st, 2007, 09:09 AM   #10
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Quote:
Originally Posted by Kevin Galliford View Post
My Question:
Like alot of TV shows, IE: Trading Spaces, etc, etc. They have a group of 3-5 people all talking with lav mic's on. How do they get all of em to go into the cam? A on cam mixing device? I dont seem to find them anywhere. I usually see the sound guy have a pack on with all these antennas sticking out of it, is he controlling all of them? But I dont have a extra guy to do this.
.
The answer is they do have a sound man or Department (multiple people) who is/are mixing multiple radio mics onto one or two channels and may be simultaneously recording iso tracks on a seperate recording device in case they don't like the mix. If you don't have the money/personnel for this then you will find it very difficult to duplicate this style.
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Old July 31st, 2007, 07:08 PM   #11
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[QUOTE=Sara Cantor;720975]Bill,


The mic packs are both Sennheiser G2 evolutions. They come with both mini and XLR cables. Assuming that I don't rent a mixer, but I do buy an interface device such as the Canon MA-300 or the BeachTek DXA-4P, will it work to plug one mic receiver into one XLR input, and the other into the other? This is starting to seem like the most realistic course of action.

It shoud work fine.

The thing you want to do is send the signal from one mic to one channel - and send the signal from the other mic to the other channel. This way you have separate recordings of each participant. This is useful because if one participant has a loud (or soft) voice, you can adjust the levels independently in post - something you can't do if the two mic signals are mixed together.

(It's helpful to think of sound as a bit like paint. Once you mix the blue and yellow to make green, there's NO way to get either original color back. Once sound is mixed, it's MIXED.)

Whichever adaptor you choose, make sure it's settings are such that you separate the individual mic signals to your cameras separate channels and you'll be fine.

Have a great shoot!
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Old August 2nd, 2007, 12:41 PM   #12
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If the camera is able to split the channels effectively then you will get one mic on channel one and the other on channel two.
Cameras with native XLR inputs always have these two, totally seperated channels where one is the on camera microphone and the other is the boom/lav microphone. If you want more mics, or more control over the input, then you need a portable mixer and someone to operate it.
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Old August 2nd, 2007, 01:21 PM   #13
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Thanks to both of you for this advice.

I bought the BeachTek DXA-4P, which is custom-fitted to my Canon GL2. Its manual says to keep the switches on Mic (not Line) if I'm using two microphones, and to keep the trim controls all the way up to maximize signal-to-noise ratio. It also says that if I need to adjust audio during shooting, I should use the camera's controls, not the controls on the adapter.

I've got one Sennheiser Evolution 100-series, and one 300-series. They have the same microphone element, so they should capture the same sound pattern. But is there anything to look out for when using two microphones of different models?

Thanks again - I'm so excited for the shoot on Saturday!

Sara
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Old August 2nd, 2007, 03:55 PM   #14
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Quote:
Originally Posted by Sara Cantor View Post
...They have the same microphone element, so they should capture the same sound pattern. But is there anything to look out for when using two microphones of different models?...
Sorry if this is too obvious, but, make sure they're on different frequencies!

You're right, the same mic element is probably the most important thing to getting the sound close. However, every person has their own voice, and will sound different anyways. I've done some mixing and matching of different mic elements in my time. But identical elements is good.

You may also be aware that there are multiple output levels available from these receivers, the hottest is essentially line-level. You'll need to go into the menu to adjust the receiver output level down to mic-level.

Keep the DXA-4p mono/stereo switch on "stereo", which will allow you to later mix the two mics while editing, rather than during the shoot, and *always* monitor the camera audio with headphones. Always.
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Old August 2nd, 2007, 04:45 PM   #15
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Thanks Seth. Not too obvious at all.
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