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Old August 14th, 2008, 06:17 PM   #1
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Lavs and Distance Between Talent

I am just now purchasing my second Sennheiser Evolution G2 100 Series wireless lavalier mic kit. I needed the second mic setup because I now have a need to record an interview of TWO people who are standing next to each other, separated from one another by about a foot or so.

I will be shooting this with a Panasonic AG-HVX200. Up until now I've only ever videotaped one person at a time so this is where my questions come in:

1) Do I have to be concerned about how close they are standing next to each other - in other words that while one of them is talking that their sound is actually being captured by the lavalier mic placed on the other person?

I had planned on having each wireless mic receiver plugged into a different channel of my HVX200 so that I will have separate tracks to work with but still that won't address the audio bleed that I am concerned about (if "audio bleed" makes any sense as a term!)


2) Is there anything special I need to be thinking about in terms of lavalier placement?

Thanks!

Steve

Last edited by Steve Crow; August 14th, 2008 at 06:31 PM. Reason: grammar
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Old August 14th, 2008, 06:21 PM   #2
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One mic

Steve,

In many cases, if you are that close, one mic might actually work for both people.

Jack
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Old August 14th, 2008, 06:26 PM   #3
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Thanks Jack....heck, I already spent the money but you got me thinking!

I could return it but I like these mics a lot and maybe having two is a more "professional" setup for this kind of situation? With one mic wouldn't the person not wearing a mic be fainter than the other? Also the sound from both people would all be on one channel.

Oh, I should have mentioned that both mics have the standard ME2 capsule if that makes any difference to this discussion.
Steve
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Old August 14th, 2008, 07:33 PM   #4
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if its an omni capsule and they are almost shoulder to shoulder, one mic can often cover both people IF its on the inside position. I've done it. yes the person further away will be lower, but if one tends to talk louder then the other, mic the lower person.

with 2 lavs, you have to duck each mic in post, opening up the active mic or you will have more noise in the mix, and potential phase problems due to the mics being too close and / or the diaphragms being at different angles. with matched mics this is less of a problem.

however, once they get a little further apart, one mic per person is standard procedure.
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Old August 14th, 2008, 07:50 PM   #5
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Make sure that both mics are in phase this should be OK if you are using the stock heads, do a mono check with the two mics side by side in mono and they should not be phasey or like the mid range has disappeared.

Yes one omni mic is capable of picking up both sides but if you set up the gain on each transmitter carefully you will get very good separation from each subject. do not push the levels too much as you can always boost them later.

if you do it really well you could even use just one receiver from the two transmitters to down mix to one channel but you didnt hear an ex pro like me tell you that did you!!!
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Old August 14th, 2008, 07:51 PM   #6
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The magic number is three. The distance between the mics should be three times the distance the mics are from their source to avoid phase issues if leaving both mics "hot".

For example: each mic is at sternum level on each speaker resulting in 1' distance from the speakers mouth. The mics are 4' apart. You're good. If the mics are 2' apart from each other, you've got problems and you'll need to aggressively "duck" in post.
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Old August 14th, 2008, 10:19 PM   #7
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Quote:
Originally Posted by Gary Nattrass View Post
if you do it really well you could even use just one receiver from the two transmitters to down mix to one channel but you didnt hear an ex pro like me tell you that did you!!!
that does not work. not any time I ever tried it. not with lectros. the reason it doesn't work is the small variances between the two transmitters cause phase cancelations leading to hissing , fizzing, and the transmitter normally passing only ONE signal due to the phase lock loop locking to the phase of ONE transmitter. maybe a cheap setup without a PLL in the front end will do this, but not a pro level system I've ever run into. if it could be done, we'd all do it. this has never ever resulted in a working setup. if you can tell us how you can do this reliably without problems, all ears
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Old August 15th, 2008, 03:06 AM   #8
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What total rubbish! Sorry, but two transmitters on one receiver? Well, this means putting them on the same channel and if you do the result can never work. The physics simply put a stop to it. While it is true that it is possible to have two wide area transmitters on the same channel, sometimes used here in the UK for things like ambulances where one control needs to talk to a large county by three or four high power transmitters - there are many problems requiring complex planning. FM reception has something calld capture effect, where when two transmitters are in use, the strongest one usually wins - BUT the other one needs to be significantly lower unless unwanted background artefacts tend to intrude.

I work in theatres a fair bit with radio mic systems and the nasty noises caused by two transmitters on the same channel are very obvious.

So the only time two channels can share a frequency is with sophisticated digital systems that can interleave two or more together, with error correction for clashing data packets.

With things like Sennheisers and other analogue current products any attempt to share a channel is doomed. Multiple receivers and a single transmitter is of course fine!
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Old August 15th, 2008, 04:23 AM   #9
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I was joking of course but there are no smilies here so I couldnt put one after the comment!
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Old August 15th, 2008, 06:10 AM   #10
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Steve,

Split track the audio; one voice per channel. Checkerboard it in post.

Regards,

Ty Ford
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Old August 15th, 2008, 06:13 AM   #11
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Quote:
Originally Posted by Gary Nattrass View Post
if you do it really well you could even use just one receiver from the two transmitters to down mix to one channel but you didnt hear an ex pro like me tell you that did you!!!
Gary,

What system do you use that allows you to use two transmitters with one receiver?

Regards,

Ty Ford
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Old August 15th, 2008, 11:25 AM   #12
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One tip on the camera side, there is a cool little shoe attachment you can get that will hold three wireless receivers. I have one of these and use it when we have a couple of wireless on the camera. It also allows you to keep the receivers straight up, or straight down, which will help extend the range rather than having the antennas horizontal. (Parallel to the ground)
You can search for it at Markertek.com it's called the Mic Mate. For some reason the link won't show up in the post correctly.

The mic mate works well with the Sennheiser Evolution G2 and the new Sony UWP series The Sony UWP-V6 Wireless System with Lavalier and Plug on Transmitter at DVcreators.net

Actually the new Sony's are kinda cool. The antenna tilts so you can point them any direction you want. Something tells me the Evolution G3 might do the same :)
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Old August 15th, 2008, 11:58 AM   #13
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Thanks everyone for such a lively discussion!
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