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-   -   Understanding Lav mics (https://www.dvinfo.net/forum/all-things-audio/472344-understanding-lav-mics.html)

Jason McDonald February 6th, 2010 02:22 AM

Understanding Lav mics
 
OK...I'm trying to educate myself in the field of audio, which is a proving to be more difficult than I expected.

When using a HDSLR like the 7D (Which I own), how does a lav mic work? I keep hearing that the standard is the Sennheiser G2's. How does this work exactly? Do I have the transmitter on the talent with the mic up near the mouth and the receiver on the rig hooked into the H4n (This is what I have)? Does the receiver then capture the audio and recorder it in the H4n? Can you/should you have a different brand mic on the transmitter according to the type of recording you're using.

Currently, as an amateur video man I'm trying to learn how to capture audio that best represents what I'm trying to present to the audience. In the video below I had a Rode Stereo Video mic plugged into the H4n with the -10db setting on as well as the deadcat. I was close to the stage and with people around me I thought the deadcat would be necessary. For some reason the audio, in the beginning anyways, had an echo to it.

I couldn't (And wouldn't know how) to get into the mixer/sound board the audio was going through. I will be attending concerts of this talent's in the future and would like to better understand how to capture via lav mic. Understanding how they work would be a start lol.

Regards,

Jason


Perrone Ford February 6th, 2010 03:11 AM

A lav works the same as any other microphone. They are just smaller. And what camera you have is immaterial to how they work.

The Senn. G2 is not a lav mic (though one does come in the box). The Senn G2. is a wireless transmitter/receiver system. It's basically a virtual wire. That's all it is.

The lav mic goes on the talent. The lav mic plugs into the transmitter. The receiver plugs into the recording device, and the recording device records the signal.

In terms of "brands" that's not really the difference. Different lav mics (just like other kinds of mics) sound different. The brand has nothing to do with it. So you need to spend some time learning about how different microphones sound, which characteristics in a microhone make them sound like they do, and learning how to select one for the different talent you have. This takes time and practice.

Learning to get "decent" audio isn't hard. Learning to get "great" audio is a skill that can take quite some time. Decent audio begins by working with decent gear, and getting the microphone as close to the talent as you can. Lav mics do not go near the mouth. They go near the breastplate. The resonance in chest cavity provides the bass sounds. Placing the mic near the mouth will guarantee they sound thin. This is especially noticeable on female talent because their voices to be more thin anyway.

Recording audio off the sound board is a terrific idea if you can get it. Actually, might be nice to get both. But that is not always possible.

Steve House February 6th, 2010 05:56 AM

Quote:

Originally Posted by Jason McDonald (Post 1482285)
...
Currently, as an amateur video man I'm trying to learn how to capture audio that best represents what I'm trying to present to the audience. In the video below I had a Rode Stereo Video mic plugged into the H4n with the -10db setting on as well as the deadcat. I was close to the stage and with people around me I thought the deadcat would be necessary. For some reason the audio, in the beginning anyways, had an echo to it.

I couldn't (And wouldn't know how) to get into the mixer/sound board the audio was going through. I will be attending concerts of this talent's in the future and would like to better understand how to capture via lav mic. Understanding how they work would be a start lol.

Regards,

Jason

I Feel Pretty - Chigusa on Vimeo

The reverb (what you are calling "echo") is caused in part by the distance your mic is from the talent. An X/Y stereo mic like the Rode SVM should be much closer to her mouth, the exact distance determined by experimentation. I'd start with putting it on a stand about 1 meter in front of her. The dead cat is intended to cut down wind noise when you're in a strong breeze outdoors and is not needed indoors. It doesn't affect the echo. The standard foam is adequate protection from the slight air movement found inside.

Using a lav mic with this woman would require some female assistance or you would need to know her well so she was comfortable with you being with her as she dressed for the concert and your touching her in order to rig the mic. My first thought would be to clip the little mic capsule on the inside of the point of the "V" of the bodice of her dress just sticking up over the edge of the fabric. The cable would lead down under her dress and around her waist to come out in the small of her back where the wireless transmitter would be clipped. Some performers might wear the transmitter clipped to a belt under the dress or in a pouch strapped to her thigh - it all depends on the mechanics of her costume. Another very common arrangment for stage performers is a small headworn mic like a little mini-headset - they're almost invisible from the audience - going to the wireless transmitter on their back. See this picture of one ... E6i Omni Earset Mic - Countryman Associates, Inc.

Perrone Ford February 6th, 2010 06:11 AM

She also has enough hair to get away with a "halo" rig, or a taped "over ear" mic. But none of those options would be as effective as a chest-worn lav in my opinion.

Jason McDonald February 6th, 2010 07:20 AM

So if I were to buy a lav kit (I see them in kits) would there be 3 parts? I mic, hooked to the transmitter that sends a signal to the receiver that is plugged into the recorder that records the music?

Perrone Ford February 6th, 2010 07:38 AM

Quote:

Originally Posted by Jason McDonald (Post 1482334)
So if I were to buy a lav kit (I see them in kits) would there be 3 parts? I mic, hooked to the transmitter that sends a signal to the receiver that is plugged into the recorder that records the music?

I don't know. Send me a link to a "kit" and I'll take a look. If there is any word that just hits me as a pet peeve, it's the word "kit". It's totally ambiguous and generally means the customer is about to get bent over.

Nathan Moody February 6th, 2010 12:27 PM

Quote:

Originally Posted by Jason McDonald (Post 1482334)
So if I were to buy a lav kit (I see them in kits) would there be 3 parts? I mic, hooked to the transmitter that sends a signal to the receiver that is plugged into the recorder that records the music?

I'm not quite clear on what you're trying to record, or why, and that matters a lot. A lav is just one mic; in the sample you provided, are you going for an isolated track of the vocal performance and an isolated track of the piano (in mono)? If you're after a cleaner mix of all onstage sound without relying on a distant mic (relative to the sound sources) mounted on your camera, one lav isn't gonna get you there. A mix sent from the main sound board will, and it can be in stereo, mixed by someone with more experience, and you can take it right into your H4. Remember, if you use your 7D's internal audio as nothing more than a scratch track for sync, heck, your H4 doesn't need to be even NEAR your camera - it can sit on the mixing board taking the mixer-provided stereo send, and you just sync it all in post. If you're recording in a venue, you've gotta make friends with the sound person/mixer, or your life's gonna get complicated, lav or hardwired mix or not.

If you're dead set on lavs, though, then yes, those are the components, yeah, but as Perrone said, one may not want to buy 3 of those 4 components in a pre-made kit. Usually the lavs that come in wireless kits are not the best; pro's often keep them as last-resort backups or "stunt mics" for dicey conditions or action.

If you can rent audio gear in your area - or are willing to rent from the reputable houses in LA, like Coffey Sound or Location Audio - the best thing would be to rent a wireless transmitter and receiver and a number of different lavs, and test the for your use and see what's best. There is no single best lav (or lens, or mic, or camera) for any one purpose. Be sure to get the right kind of wiring and connector on the lav for the wireless transmission system you're using: they're all different and not interchangeable.

It's also pretty important to buy two lavs per wireless system as backups when recording performances, since the smaller components can and do break. It's a tricky budget issue, as pricier mics are tougher, but if the tougher mic does fail at some point, you're SOL if you don't have any sort of backup. You can always use a cheaper mic as a backup, of course, if you're budget-constrained, but I find truly duplicate mics as backups are more predictable to use, rig, and place.

I can't emphasis enough how important testing, practice, and proper lav placement/rigging is! It's a great set of skills to have, but it's a deep hole and there's a lot to learn!

Jason McDonald February 7th, 2010 07:56 AM

Quote:

Originally Posted by Perrone Ford (Post 1482340)
I don't know. Send me a link to a "kit" and I'll take a look. If there is any word that just hits me as a pet peeve, it's the word "kit". It's totally ambiguous and generally means the customer is about to get bent over.

As an example
Buy Sennheiser ew 112-p G3 Omni Lavalier Microphone Wireless System | Lavalier Microphone Wireless Systems | Musician's Friend

This is a hobby and I don't see myself breaking into the business of video BUT I do want to have fun, learn and maybe be good enough someday to consider a career change. Right now, I'm just learning.

The clip above was practice, again. I have plenty of opportunities to see these talents perform. I don't know about getting access to the mixer.

I would like to make a few short narratives if time permits. I'd like to work with good audio, but need to be able to do it on my own.

As for renting, I'd have to look around. Japan is not big on renting pro gear of any sort from experience.

Paul Hudson February 7th, 2010 08:23 AM

I am not sure I would consider the G2 the standard, just an inexpensive alternative to the much preferred Lectrosonics.

Paul
Lizardlandvideo.com
Phoenix Video Production

Steve House February 7th, 2010 08:42 AM

Quote:

Originally Posted by Jason McDonald (Post 1482765)
As an example
Buy Sennheiser ew 112-p G3 Omni Lavalier Microphone Wireless System | Lavalier Microphone Wireless Systems | Musician's Friend
...
The clip above was practice, again. I have plenty of opportunities to see these talents perform. I don't know about getting access to the mixer.
...
As for renting, I'd have to look around. Japan is not big on renting pro gear of any sort from experience.

Do you have access to the talent herself before the performance. Remember a lav is something she has to wear attached on her person. And if she's wearing a lav, as others have mentioned, you'll also need to mic the piano.

You say you don't know about getting access to the mixer. You get access by finding out who is handling front-of-house sound, going up to him or her and introducing yourself.

The G3 is a good entry level prosumer unit. Sony and Audio Technica also have units that are well received in the same general price range. Going cheaper is not advised, generally getting you mediocre performing consumer toys or worse. On the other end, Lectrosonics and Zaxcom are mainstream pro in North America but be prepared for sticker shock if you go there.

Jason McDonald February 7th, 2010 11:08 PM

I do have access to the talents. They are friends. Having them wear a lav for a performance is just a matter of asking them.

The places they perform at are lounges that allow up-and-coming talent to perform to an audience of mostly family and friends. I could ask the sound person to get access to the mixer, but what should I do if he says 'I'm not sure how to set your H4n to the mixer'

Perrone Ford February 7th, 2010 11:54 PM

Quote:

Originally Posted by Jason McDonald (Post 1482765)
As an example
Buy Sennheiser ew 112-p G3 Omni Lavalier Microphone Wireless System | Lavalier Microphone Wireless Systems | Musician's Friend

This is a hobby and I don't see myself breaking into the business of video BUT I do want to have fun, learn and maybe be good enough someday to consider a career change. Right now, I'm just learning.

Fair enough. The kit you linked to is ok to get your started. I ordered something similar for my needs but took the advice of many pro's and changed the mic out to a Countryman. I would have gotten the Sanken Cos-11x, but couldn't afford that one.

The mic that comes in the kit is good enough to practice with. I would not advise worrying about hiding the mic at this point. She's not on TV. Frankly, if these are singers and you really want to do this, I'd be looking at a good vocal mic and putting a wireless transmitter on THAT instead of fooling around with a lav. The sound will be better most likely and it will give them something to do with their hands.

Mark Boyer February 8th, 2010 11:42 AM

1 Attachment(s)
This will answer all of your questions: Location Audio Simplified
Location Audio Simplified - Books & Videos - Trew Audio

Also... do you wear headphones when recording?

Peer Landa February 9th, 2010 04:12 AM

Quote:

Originally Posted by Jason McDonald (Post 1482285)
OK...I'm trying to educate myself in the field of audio, which is a proving to be more difficult than I expected. When using a HDSLR like the 7D (Which I own), how does a lav mic work? [...] Currently, as an amateur video man I'm trying to learn how to capture audio that best represents what I'm trying to present to the audience. [...] I couldn't (And wouldn't know how) to get into the mixer/sound board the audio was going through.

Quote:

Originally Posted by Perrone Ford (Post 1482289)
Learning to get "decent" audio isn't hard. Learning to get "great" audio is a skill that can take quite some time.

For my 5DMKII (similar to your 7D) I'm using a Sennheiser G3 lav kit along with an onboard Ambient shotgun mic and their tiny mixer (that routes the two signals into the camera), and then in post I'd later balance/mix the two. If the stage sound is really critical, I'd also use a Sony PCM D1/D50 as a dual system. Here's a silly video showing the shotgun mic and the on-camera mixer:

-- peer


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