GH4 audio bug discovered

As I mentioned before, you have to use a 3.5 to XLR that blocks the power coming out of the audio jack. No different than any other powered plug from the past. In fact, the need for isolation has been around since 2009 with the first 5DMKii. Luckily I still have my adapters from then.
 
Great to hear that they've narrowed down the problem. Pretty damn responsive, if you ask me. I'm impressed.
 
Sorry guys, but their solution doesn't make sense to me at all. Why do I have to go through all the hustle of buying their s*%tty overpriced mics, adapters (which may not work), or soldering etc just to use the mic (in my case Rode VideoMic Pro) that works on any other camera I plug it into and simply should work with GH4. I wish I could add to that Facebook thread, but I can't (don't use Facebook).
 
Bravo to Panny for jumping on this so quickly, but you should still be able to use any microphone with a industry standard 3.5mm TRS connector. If the same mic doesn't buzz in the GH1, GH2, GH3- it shouldn't be the customer's responsibility to only use Panasonic mics now with the GH4.
 
Here's the thing, I've been testing the issue extensively and the buzz is present even without any mic connected. The buzz is audible with the built-in mic as well, but you have to isolate the mics from other noise (room tone, etc.) to hear it more clearly.

I'm working on a full post about my testing with this issue.
 
Okay, I've done a lot of tests regarding this issue. Here are my findings in a nutshell:


  • The GH4 has an audible buzz/fluttering that is present in all recording modes (AVCHD/MP4/MOV, 4K/1080P, NTSC/PAL/Cinema, etc.)
  • The frequency of the buzz is affected by shutter speed and other camera functions
  • The buzz is always there: It is present whether or not a microphone is plugged into the GH4 and at all audio gain levels.

I've written a post of my findings on my blog for anyone interested in the full details and audio samples.
 
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Your page is a little confusing on if this is just the headphone monitoring that has buzz or the buzz is actually recorded to the file. Everyone else says the video recording does not have the buzz and it is just on the headphone monitoring, are you saying the buzz is actually being recorded in-camera?
 
I have yet to encounter this problem. I recorded a music video with the Rode Videomic Pro set to +0dB and GH4 set to -12dB and I heard no buzzing. Here's the video, see for yourself.


Furthermore, I recorded a sit down interview in a quiet space this morning and I heard no buzzing. My set up: a Rode NT3 into a Sound Devices MixPre through a -35dB L Pad Attenuator cable into the GH4 with its audio levels at -12dB. That's how I expect to record all my interviews, so I don't see this buzzing being a problem for me.
 
thedarkhorse said:
Your page is a little confusing on if this is just the headphone monitoring that has buzz or the buzz is actually recorded to the file. Everyone else says the video recording does not have the buzz and it is just on the headphone monitoring, are you saying the buzz is actually being recorded in-camera?
Click to expand...

Sorry for the confusion. The buzz is definitely recorded to the clip. The audio samples in the post are pulled directly from clips recorded by the GH4.

Benjobe said:
I have yet to encounter this problem. I recorded a music video with the Rode Videomic Pro set to +0dB and GH4 set to -12dB and I heard no buzzing. Here's the video, see for yourself.

Furthermore, I recorded a sit down interview in a quiet space this morning and I heard no buzzing. My set up: a Rode NT3 into a Sound Devices MixPre through a -35dB L Pad Attenuator cable into the GH4 with its audio levels at -12dB. That's how I expect to record all my interviews, so I don't see this buzzing being a problem for me.
Click to expand...

As mentioned throughout this thread, you will not hear the buzz at -12dB. That doesn't mean it's not there though. If you're not concerned with a buzz under your audio that may affect your ability to further process the audio in post, then this issue likely won't affect you.
 
Sol M. said:
As mentioned throughout this thread, you will not hear the buzz at -12dB. That doesn't mean it's not there though.
Click to expand...

So is the buzz recorded with the GH4 audio level set to -12 dB ?

Benjobe sent some audio tests to me that he performed with his Sound Devices MixPre as per the instructions I posted, and the recording with the camera set to -9 dB the WAV file displayed the same -63 dB RMS noise-floor that both my GH3 and HMC-150 camera do.

i.e. the self-noise of the camera was showing at -63 dB, with no audio louder than -63 dB being recorded

Listening to the audio test WAV files with Sony 7506 headphones I could not hear anything other than dead silence under normal listening conditions.
 
...I am wondering if people are noticing the normal -63 dB RMS noise-floor of the GH3 and GH4 cameras ?

i.e. If you boost the normal -63 dB RMS noise-floor by 10 dB it will start to become audible with good sound systems. If you boost your audio levels by 20 dB it will start to sound like frying-eggs.
 
TheDingo said:
So is the buzz recorded with the GH4 audio level set to -12 dB ?
Click to expand...

This is an example of the buzz recorded by the Panasonic GH4 when using the in-camera mic with audio gain set to -12dB (normalized).

https://soundcloud.com/solmarch/panasonic-gh4-audio-buzz-external-mic-min-gain

Settings:
  • Mode: Movie (M)/24P/100mbps/MOV
  • Shutter Speed: 1/160
  • Aperture: f/1.4
  • Lens: Panasonic 25mm f/1.4

There are more samples at the blog post I linked to above. Video demo is currently rendering.
 
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Sol M. said:
This is an example of the buzz recorded by the Panasonic GH4 when using the in-camera mic with audio gain set to -12dB (normalized).
Click to expand...

...But this audio has been boosted in post, hasn't it ?

Meaning if you took a raw video clip and threw it on your NLE you would not hear the buzz at this level without boosting the audio levels. Yes?
 
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