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Old November 18th, 2009, 08:31 PM   #1
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Concert Filming - audio too loud for mic?

I'm not huge on audio so excuse me if this is basic stuff. My equipment first: XHA1 with RODE NTG2 microphone.

I filmed a concert with unfortunate results on the audio side. Thankfully it wasn't a paid gig so I shouldn't get in much trouble. Anyway, while I was filming I noticed that even though I turned the audio level down, the audio was still sounding distorted through my headphones. I looked through some camera audio settings and couldn't find anything that might help. It was too late to do anything about, so I left it knowing the band is just watching it to critique themselves and not for marketing purposes or anything, but I'm still upset that I can't use the footage for it if i I wanted to. I read some pretty good reviews on the NTG2 mic so I guess I was expected a lot better.

So, was the concert simply too loud for the mic? Or is there something I can do to control how much the mic picks up?

Thanks in advance!
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Old November 18th, 2009, 08:53 PM   #2
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From a collegue's experience and several threads here, it appears that the NTG2 tends to overload at relatively lower spl's than some other mikes. You might have better luck with the AKG Perception 170, AKG C451B or Sennheiser E914 mikes, which tolerate around 155 db. If you search for NTG2 and AKG perception 170 here, there is a thread from several months ago with a/b clips of the two mikes at a loud venue.../Battle Vaughan
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Old November 18th, 2009, 09:19 PM   #3
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They tolerate 155db? wow.. that's extremely loud! Way beyond the threshold of pain... I bought an Oktava MK-012 that came with a -10db filter, but i've never tried it with the filter.. I wonder how effective that mic would be with high spl levels? It seems like a great mic for the money, especially since it came with 3 heads (cardioid, hypercardioid, and omni).
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Old November 18th, 2009, 09:43 PM   #4
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This sounds like one of two things:

Preamp quality or issue

or

Impedance mismatch between the mic output and the pre-amp input.

The problem with many more affordable video cameras is that the preamps are setup mainly to work with weaker mics. These mics output a weak signal to the preamp which amplifies it a certain amount for proper levels.

Recording mics output a lot more signal which overloads the preamp no matter what the volume of the recorded material.

If you plugged that same mic into a decent computer recording device, your levels would not overload the preamps because they are set at a lower impedance.

Check to see if you can change any settings in the camera to "attenuate" the signal. This is usually given as -60, -50 or -40 with -40 needing the most signal to achieve good levels as well as being the "cleanest".

Hope this helps!
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Old November 18th, 2009, 10:19 PM   #5
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My Sennheiser ME66, similar to the NTG-2 in a lot of respects, overloads at the MIC stage (NOT the preamp stage) at loud rock concerts so I have no reason to believe that the NTG-2 wouldn't as well. I've used the onboard attenuators and external pads to no avail. At SOME point, the SPL's are just too much for the moving parts in the mic to function properly. I usually bring along a medium diaphragm condenser on a stand and use that instead. Works like a charm!
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Old November 18th, 2009, 10:27 PM   #6
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You may have experienced a simple case of mic overload. The problem starts before any of the electronics get involved. The mic's diaphragm simply can't travel back and forth enough to replicate the strength of acoustical waves hitting it.

The solutions are to move the mic further away from the sound source, place the mic's diaphragm away from a direct hit, or any other action that can reduce the amplitude of the wave striking the diaphragm.

If this is the case, no amount of fiddling with attenuators in the chain will help. The sound is distorted at the outset.

Dynamic mics do better with high SPL's than condensers as a general rule.

Just a thought,

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Old November 18th, 2009, 10:29 PM   #7
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Shaun typed faster than me... hehe, but yeah, we both more or less came to the same conclusion.

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Old November 18th, 2009, 11:11 PM   #8
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Quote:
Originally Posted by Greg Boston View Post

Dynamic mics do better with high SPL's than condensers as a general rule.
Hence the reason the much maligned SM58 can be used at INCHES away from the loudest rock screamer and still hold up sonically.
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Old November 18th, 2009, 11:40 PM   #9
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I don't have any experience with the NTG2 mic, but I have never had a condenser mic distort with live room audio.

Unless the filming was done on stage right next to the speakers, then I could see some problems. But this situation would not be ideal anyway.

If the OP was at any distance from the stage, then I would think SPL would not be an issue or the people in the audience would be hurting.

If you record a lot of music, I really like my Peluso condensers. $350 and they sound great. Not far from the Rode price and they can handle everything you can throw at it.

I am negative on some camera preamps due to my past experience with the PD-170 and a recording condenser. The mic was just too hot for the camera and adding the attenuation killed all but the loud parts. It distorted very easily, yet on my larger cameras or through a recording interface could handle massive signal input.
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Old November 19th, 2009, 12:06 AM   #10
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Quote:
Originally Posted by Tim Polster View Post
I don't have any experience with the NTG2 mic, but I have never had a condenser mic distort with live room audio.
I have with Sennheisers (and others) on Sony PD150's, Z1's, BetaSX, JVC ProHD... the list goes on.

You really don't need to be THAT close either - it just needs to be a loud room.

Having said that, what I've never tried is aiming the mic AWAY from the PA speakers.
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Old November 19th, 2009, 02:33 AM   #11
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The maximum SPL doesn't tell you anything about what it sounds like even a fair bit away from the maximum. Unless they tell you the amount of distortion allowed at the level they measured at it's just a guide.

I've always used the guide that when a manufacturer gives you a pad switch, the mic needs it! These mics are often very sensitive - something everyone expects in a video mic, so the range is the problem. A Duck quacking 100m away, or a rock concert PA at 100m are VERY different in level. SPLs in music events are usually set at the mix position. Big Mick - Metallica's sound man answered a student question - "What SPL do you have at the mix position?". "I turn it up until my teeth rattle!" was the answer. It isn't just rock music. A symphony orchestra can easily overload a condenser on the fff sections. Camcorders that try to be 'set and forget' try to manage sound automatically, but without a pad, you're working at just one end of their range - so you have huge, possibly slightly distorted sound from the mic, that is harmonic rich, and then this feeds a pre-amp outside of it's capabilities, and the distortion gets worse. A mic with a pad is the easiest solution to the problem, allowing the camera system to breath a little.
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Old November 19th, 2009, 03:59 AM   #12
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Why not hook up the camera to the band's mixer? That's if it's compatible.
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Old November 19th, 2009, 04:34 AM   #13
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Hi Chris,
It sounds like you are distorting the mike insert and if that is the case nothing you do down stream will fix the problem. I have been using The Gold Line CBM1 mic which I have placed inside a kick drum to see if I could get the mike to distort and it has held up. They are a great mic for stage not really suitable to mount to a camera. I would place 4 of these around the stage and take a mix down to the camera from the audio mixer to get good clean audio.
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Old November 19th, 2009, 05:43 AM   #14
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A weak battery in the mic can reduce its maximum SPL handling ability

The mic may be able to handle the high levels while outputting a very hot signal that could overload the mic's preamps right at the camera's inputs. That would be before the camera level controls can do anything to control it. A pad on the input might have helped. Worth experimenting.
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Old November 19th, 2009, 02:33 PM   #15
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Quote:
Originally Posted by Tim Polster View Post
I don't have any experience with the NTG2 mic, but I have never had a condenser mic distort with live room audio.
I should have added that I have never had a condenser distort with live room audio going into nice quality preamps.

My condensers with the PD-170 reached distortion very easily.
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