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Audio peaking on -30db sensitivity Senn EW100G2

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MAtt Oaten
Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 11:42:35 am

Hi,

I'm having problems recording sound for a documentary i'm working on as part of an independent production company. (I'm not a sound professional, but i'm having to act as one!)

I'm using a Sennheiser ew100G2 lapel mic for interviews, and on its lowest sensitivity (-30db) the transmitter is peaking, giving me distortion. I'm not running it through a mixer, just straight into the cam from the receiver, peaking at about -6. I'm really happy with the quality of sound we're getting, it's just that on exceptionally loud bursts of laughter etc it sounds rather horrid.

Does anyone have any tips? I can imagine it's something simple....

Thanks in anticipation,


Matt Oaten


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David Jones
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 3:22:32 pm

Hi Matt-

I don't mean to be "that guy" but that's why you need a mixer :o)

Basically, you need a limiter to prevent the loud peaks in your audio, which are causing distortion. The only other thing you can do is switch the audio setting on the camera from manual to auto. This is really an AGC or auto gain setting which will help in loud peaks, but it also increases the noise floor when no sound is present.

Dave J


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MAtt Oaten
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 3:38:30 pm

Yeah, that is a work around, but one of the reason we're using lapel's and not a nice boom is to try and eliminate the background noise (some interviews taking place in odd, uncontrollable locations) so it's not something we wanted to do really.

So I think it's now that I learn that we need more money, more crew and better kit! If we had a field mixer, will it have a built in limiter that would stop this peaking?

We have a really good post house lined up to do the sound mix/design, and I want to give them the best quality possible. Any other tips and work arounds most welcome!

Cheers for your valuable input,

Matt


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Jordan Wolf
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 4:43:35 pm

If the signal is already hot enough, move the microphone away from the source (mouth/chest) a little bit.

Sometimes, if you mic a person too low on the chest, it will be a very strong level due to the resonance of the chest cavity. To avoid this, I usually put the lapel mic no lower than just above the third button on a button-down shirt. Try to find a happy medium for your situation, and if you're sending it to a good post house, they should be able to spruce it up with some EQ.

Have fun!

Wolf
<><


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David Jones
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 5:46:34 pm

Using the lav mic is not your problem, and neither is using the Sennheiser wireless; it's the fact that you don't have any way to really control the peaks (or the levels for that matter). This, too, would be the case if you were using a boom mic.

Any field mixer will have limiters. If is doesn't, don't buy it :o) I would recommend the Sound Devices 302 or 442.

Dave J


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Jordan Wolf
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 7:50:37 pm

Matt,

What do you mean by "peaking" the transmitter?

Do you mean:
a) The "AF Peak" light keeps lighting up.

OR

b) The levels you are getting at the receiver are too loud, causing your camera's inputs to overload.

See, I've been reading your post and it seems to me like this isn't an issue at the camera's inputs. This really seems like an issue that is at the transmitter - especially if it is peaking. If the transmitter is peaking, there is NOTHING you can do to fix that further down the signal chain.

Wolf
<><


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MAtt Oaten
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 31, 2009 at 8:42:23 am

Yes, it is a transmitter problem! In camera I have the audio peaking at -6db, no problem camera-side.

It is the transmitter that is peaking. If I lower the sensitivity of the receiver (currently at -12db) will this help to eliminate the problem of the peaked sound reaching the camera?

Thanks

Matt


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John Fishback
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 5:30:55 pm

Many cameras have built-in limiters, but they have to be turned on. You should check to see if your camera has that capability.

John

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George Burbano
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 27, 2009 at 9:51:09 pm

I use this same setup to record interviews and never run it through a mixer.

You need to do sound checks where you are shooting.

1. do a sound check without dropping the sensitivity of the transmitter
2. Listen to the sound that you are getting at your camera through headphones. Try and adjust the manual audio setup on your camera.
If its too hot, (too loud or distorted) then start dropping the audio output level on the "RECEIVER" first.

It may not be the transmitter that is overdriving, it probably is the receiver. Once you are no longer getting distorted sound, then adjust your levels at the reciever. and readjust at the camera.

You only need a mixer if you are recording multiple seperate audio, and feed it to the 2 channels on a recorder or the camera. Example several lavs or mikes into two channels. You dont need to spend $1500+ on a good mixer, you just need to do a sound check and audio adjustments

By the way, most lavs are omni directional where a good boom, would probably work better well placed. Unless everyone is moving around, you can place it on a matthews or similar stand, and put it higher than the camera can see, above their heads.

Experiment with what you have before you go and get what you dont have or may not need..

Just my thoughts.

George






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Ty Ford
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 28, 2009 at 3:12:23 am

OK, everyone has had a go-round. Now let me.

Good mixers like the 302 and 442 with limiters absolutely can improve your audio, provided you know how to use them.

Mixers are more than knobs that let you vary the volume.

1. They let you vary volumes without shaking the camera or getting in the way of the camera op.
2. You may need to do that a lot with some people. I ride gain even if one person is talking if their voice fades on the end of each line. You can only do this in a relatively quiet environment, otherwise you bring up the ambient noise.
3. Mixer preamps (good ones) sound better than camera preamps.
4. Good mixers have input transformers that scrape off RF before it get into your audio.
5. Good mixers have limiters that allow you to record hotter, keeping your audio further above the noise floor without distorting.
6. Good limtiers have EQ that lets you roll of LF HVAC noise before it gets into your audio.
7. Good mixers have mulitple outputs so you can feed more than one camera, or separate recorder simultaneously.
8. Good mixers make your sound better. If they didn't pros wouldn't use them.

In addition to a good mixer (as in a piece of equipment), a knowledgeable person operating the mixer can get much better audio than simply plugging the mics into the camera.

I'm thinking two things about the original poster's problem. Something may be misadjusted, but more likely than not, the outbursts are just too loud for the settings. This happens. It's like shooting someone with bright backlighting and trying to get a good exposure on their face when it's in the shadow. The dynamic range of the light to dark is too great for the camera.

BTW, I have never hear a voice get louder on a lave if the lav is placed farther down the chest.

Regards,

Ty Ford




Want better production audio?: Ty Ford's Audio Bootcamp Field Guide






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George Burbano
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 29, 2009 at 1:40:30 am

You are right Ty. The problem I see here, is this gentleman is having an issue, because he is not familiar with using the equipment he has. Too many people are then telling him to go get another piece of equipment which he also wont know how to use. There is nothing wrong with the equipment he has. He just needs to know how to use it.

How to obtain proper placement of mikes and checking sound levels and setting them are not a science. They require some practice and knowledge of the equipment someone is using.

Yes a sound mixer is great and a fantastic piece of equipment when it is necessary. But he really doesnt need one, he just needs to learn how to set up and use the equipment he has.

I like the reference of the lighting problem that many encounter also
Another problem that many do not know how to address. Things like Key Shifting, basics of lighting are things that perplex many starting photographers, videographers or cinematographers. Things that require the basics.... Whether lighting, camera operation, audio or even advanced things like post production. All require a basic understanding of operating and working equipment. If money was of no object, our equipment would have no limits. But.........

YOu still have to have the basics..


George




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MAtt Oaten
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 31, 2009 at 8:59:31 am

Yep, I completely agree! I'm in-experienced at recording sound, and i'm striving to get the best possible quality with the time and equipment I have at my disposal.

I'm going to run a few experiments this week and hopefully combat the issue. I think a combination of repositioning the mic a little lower, and lowering the sensitivity of the receiver should help (fingers crossed)

Thanks for everyone's input on this thread,


Matt


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Ty Ford
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 31, 2009 at 11:45:04 am

Matt,

What part of the world are you in?

Ty Ford

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide






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MAtt Oaten
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 31, 2009 at 11:57:19 am

I'm in London, UK!



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Ty Ford
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 31, 2009 at 12:15:01 pm

OK, if I were you, I'd find a shop in London where this stuff is sold and take the camera and mic in to see if there was someone who could show you hands on.

Regards,

Ty Ford

Want better production audio?: Ty Ford's Audio Bootcamp Field Guide






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Jordan Wolf
Re: Audio peaking on -30db sensitivity Senn EW100G2
on Mar 31, 2009 at 1:58:49 pm

Matt,

You can e-mail me at jwolfbiz@gmail.com if you would like more help.

Wolf
<><


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