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    #21
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    It seems like this distortion being caused is a result of excessive sound pressure on the microphone in use. This would most certainly cause audible distortion on any recording devise.
    I'm not a sound expect by any means, but I would think that it's easier to distort a condenser mic as compared to a dynamic mic, especially a condenser shotgun which is designed to bring sounds that are further away closer, in audible terms ( and rejecting off access sound). I think this is why I was able to replicate the problem with the ME66 and could not with a dynamic mic.

    Now My question to you Chris is...

    Wouldn't this distortion occur on any camera along with the signal being recorded, because the mic is being overloaded?
    The issue in question here is why is it occurring on the HPX250 with the level pots turned down to no gain?
    I did another test with the ME66 and did not purposely overload the mic, and the recording was fine with no audible distortion.

    It would seem that maybe the preamps in the HPX250 are a little more sensitive than others, maybe 0 gain on the level controls is not really 0 gain.
    Not high enough to record a normal signal, but just able to pass through the clipping distortion that occurs on an overloaded microphone?

    Certainly microphone choice is critical with any camera depending upon your particular situation, and if in an extremely loud environment it may be wise to choose
    a less sensitive mic.

    Does this seem Valid?
    Last edited by mmaller; 04-28-2012 at 06:09 AM.


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    #22
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    timbrook2 - What are the problems you have been having with the ME66?

    mmaller - I know what you are saying, this was my initial theory but all the sound guys I have spoke to said that shouldn't be the case. The ME66 has a maximum sound pressure of 125db. I'm sure the environment level I was recording in was much less than that as it was much quieter than a typical nightclub and I don't think I'm creating that much sound pressure with my voice when testing. I don't have a proper decibel metre but did just use an app I have on my iPhone and made the same sound into it that I have been doing when testing and it read 90db, again indicating that the mic can't be distorting from excessive sound pressure because its 35db shy of the maximum (I know the iPhone when be accurate but surely its not 35db out). My main concern though is that the levels when recording the venue were around -18db to -12db. When the "electronic distortion" came through it peaked over that, over riding the set levels. The sound in the room didn't rise that much at all, if anything the frequency may have increased. As before, my main gripe is with the camera not blocking that signal when the levels are at zero which all its competitors did. As far as I know, dynamic mics don't require power to run so this could be why you don't get the electronic noise when testing with that. The camera should be able to deal with both though for the level of equipment.

    I must stress that everything I say is based on loose knowledge and a bit of guessing/common sense so if I'm drastically wrong in what I'm saying, please feel free to correct me.

    I'm hoping that I'll get some definitive answers this week from Panasonic etc so I'll keep you posted.


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    #23
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    This was something that was posted on this same subject on another forum, not sure what you all think.

    That sounds like a digital encoding problem to me similar to pixelation on the video side, you can hear the digital bleeping at the end and its unlikely that mic would be making such noises, I would get in touch with panasonic under your warranty registration as it sounds like a faulty component or something is not working right on the camera to encode the audio.


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    #24
    Senior Member timbook2's Avatar
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    The ME66 was creating problems. Intermitting hums and crackles with or without phantom power, with or without battery. We checked it with a second one and it also didnt like the panasonic audio inputs. This was ONLY with the HVX200 and I got rid of it. Since then no more problems with the exact same cables! Your test (I listened to the audio) sounds like the audio hardware after the XLR input is flawed in some way. If the volume is zero nothing should enter....


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    #25
    Senior Member Jan_Crittenden's Avatar
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    Hi everyone,

    I just did a little search on Google about the ME66 being a little hot; I vaguely remembered from years ago that there was an issue with mics that are on the hot side that this can be a problem. I know that the HPX250/AC160/AC130 can use a condensor mic, but one needs to note that it is looking at a max of -40dB. I know that some Sennheisers are at -36dB(hotter than what the camera can handle). So it may well be that a different microphone choice may be in order or a small pad on the output of the mic could be used to bring it back into a useable range.

    Best,

    Jan
    Jan Crittenden Livingston
    Panasonic System Communications Corporation
    Partner Sales Manager, NY and NJ


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    #26
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    Nope, my ME80 does it also. It has less sensitivity than a ME66 and ME416. I was a recording engineer/tech 40 years, and 35 years of DPing and video tech.


    I DON'T have a problem with my HPX500, any of my Sony BetaCams, DVcams, JVC's, Canon's,etc.

    It's just ridiculous that you would have to pad a Sennheiser shotgun for a XLR input to a video camera. Name me ONE other camera that has this problem.

    Sennheisers shotguns are probably the most used shotguns in the world.
    Last edited by JohnnyD; 05-04-2012 at 11:29 AM.


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    #27
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    JohnnyD - have you had the same issue with the HPX250 then?


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    #28
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    Quote Originally Posted by Chris Dumont View Post
    JohnnyD - have you had the same issue with the HPX250 then?
    Yes. The ME80, which I like a lot better,,,AND is less sensitive, can produce that distorted sound, when everything is on manual. It does take a loud sound to make it happen, but it does happen. What's crazy, you can get that clipping even when the manual audio control is on "0", as was described at the beginning of this thread. The resistor pad on the audio pot should ground the hot signal, but somehow there is leakage.

    Probably not an issue for many, but I sometimes record in high level environment situations, and I don't want take a chance. Like I said, no problems with my other cameras. And the Sennheiser's are sweet.

    It's too bad, I really like the pic of the 250. I need to figure out if I'm going to return the camera, or work with it, by tomorrow.
    Last edited by JohnnyD; 05-06-2012 at 05:20 PM.


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    #29
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    Let is know what you do. I also use an HPX250 / ME66 combo but haven't noticed any significant issues.


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    #30
    Senior Member Mike Warren's Avatar
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    Quote Originally Posted by JohnnyD View Post
    The resistor pad on the audio pot should ground the hot signal, but somehow there is leakage.
    My educated guess is that the audio level is set digitally and the pots are simply voltage sources into the CPU. It sounds like what might happen if the input to the audio ADC is overloaded.

    Modern technology comes with a whole new set of potential problems.


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