GH4 External Mic Audio Issues and Workaround

May 23, 201419 Comments

Panasonic has announced a fix for the audio buzz. Please click HERE for the full story.

UPDATE May 27th.

Screen Shot 2014-05-27 at 11.55.34 AM

B&H today had a webcast on the GH4 with Panasonic Field Training Manager Mathew Frazer. I asked about the issue through the twitter feed with the hashtag  #BHPhotoLive to see if I could get a response. Well I did! Here is what Mathew says is the problem. In the B&H GH4 Webcast go to 1:46:00 by clicking on the progress bar. He starts about a minute after from that point and you can see Mathews explanation of what might be happening.

Mathew says they are still looking into ways to fix the issue when not using the Panasonic shotgun microphone.

Panasonic DMW-MS2 Stereo Shotgun Microphone

Panasonic DMW-MS2 Stereo Shotgun Microphone

Mathew Frazer says The problem is with the 3.5 mini connector. The GH4 is designed to work with the Panasonic DMW-MS2 Stereo Shotgun Microphone and has features that can be adjusted in the menu of the GH4. In order to have these features the mic uses this type of connector.  The pattern goes as follows. TIP-RING-RING-SLEEVE

2011-06-15-Building-an-ipad-guitar-cable-004

TIP-RING-RING-SLEEVE

Most 3.5 mini connectors use. TIP-RING-SLEEVE.

Screen Shot 2014-05-27 at 12.08.30 PM

TIP-RING-SLEEVE.

 

He says this is causing a ground issue when not using the Panasonic Shotgun microphone. He stated that maybe an adapter will solve the problem but that Panasonic engineers are still looking into it. So thats the update and I’m sure more info will be coming soon in the meantime anyone know were to get an adapter like this? Well it turns out it’s pretty simple. It’s a TRRS to TRS  adapter. I ordered this one and will give it try.

UPDATE May 29th.

I received the TRS to TRRS adapter cable and it still has the issue. Unfortunately we will have to wait until Panasonic engineers can figure out how to solve the problem with some microphones like the Rode VideoMic Pro. Sorry. I wish this would have worked.

I decided to give it one more go. I ordered the Rode SC4 3.5 TRS to TRRS adapter  I doubt this is going to make a difference but since it’s made by Rode I know for sure the adapter is what it says it is. I tried the Rode SC4 with no luck. In fact the adapter doesn’t work at all with the VideoMic Pro. No signal passes through. It is designed to be used with an iPhone so possibly the pin assignment is different.

I finally was able to duplicate the issue with my GH4. But in order to do so I had to use the RODE VideoMic Pro. My Rode Lavalier doesn’t make the clicking buzz issue. Thats the good news. Below is what the buzz sounds like. In order to make it easier to hear without cranking the audio up on your system I triple tracked it in Premiere Pro and boosted all three tracks up 6db. It doesn’t sound this bad or load but i want to hear what it does sound like.

The other good news is if you set the Rode to 0db and the GH4 to around -12db the issue seems to go away or at least not be audible. This could be considered the work around for that mic. The key here is to avoid bringing the GH4 audio setting above -12db. You can go a click up and still be fine but the higher you push the GH3 the more noise you bring in and in general that has been the rule for all DSLR’s. I’m talking about the normal kind of noise here not the clicking buzz issue.

This is a test I did for the RODE Lavalier and the GH4. Dont really focus on what I’m talking about because this test was for a review of the Rode Lavalier I did. The camera was set to -12db and I got a very good level for recording. Right after I stop talking you will hear :20 worth of  silence. I boosted the audio in post to +6db to make it more pronounced. Go ahead and crank up your speakers but…..

TURN YOUR VOLUME DOWN BEFORE :20 IS UP

As you can hear no issue with the Rode Lavalier. Now this isn’t a fix because not everybody has the Rode Lavalier and if you need a shotgun mic then a lav wont due, but I think we can at least look to it and see what makes it work and hopefully that will help fix the problem. I sure hope Panasonic can fix this with some kind of firmware update because it’s not fair to the consumer that only a few microphones will work and if Panasonic’s mics are the only solution they are offering to deal with this thats also not acceptable.

Here is the specs of the Rode Lavalier.

Acoustic Principle Pressure Gradient
Active Electronics JFET impedance converter
Capsule 0.10″
Polar Pattern
Address Type End
Frequency Range 60Hz – 18kHz
Output Impedance 3000Ω
Maximum SPL 110dB SPL (@ 1kHz, 1% THD into 1KΩ load)
Maximum Output Level 189.0mV (@ 1kHz, 1% THD into 1KΩ load)
Sensitivity -33.5dB re 1 Volt/Pascal (21.00mV @ 94 dB SPL) +/- 2 dB @ 1kHz
Equivalent Noise Level (A-weighted) 25dB-A
Weight 1.00gm
Dimensions 12.00mmH x 4.50mmW x 4.50mmD
Dimensions 12.00mmH x 4.50mmW x 4.50mmD
Output

I’m not a super engineer so if you are please dig in.

would really appreciate it if you have tested your GH4 and found other mics that do work with no issues please leave the brand and model in the comments section. This will help us determine what is usable until we find or get a fix from Panasonic.

If I find out more I will update this post. I hope I helped or at least give some kind of workaround for you.

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About the Author ()

I'm a broadcast DP In San Diego. I enjoy sharing what I'm working on and testing new equipment. This blog is also part of giving back. I've learned so much from so many people.

Comments (19)

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  1. Dave Dugdale says:

    Yep I have an issue too, see my latest video.

  2. Bill says:

    Thanks, Erik. Another reason to avoid the Videomic “Pro”, in my view. Unbalanced output and that skinny little cable and 3.5mm jack would be okay if they were charging $100 for it – but for $230 you can get a real mic.

    • Erik Naso says:

      I wish I had a hand full of mics I could test but I dont. I’m going to go back and see if my Sennheiser 2000 wireless makes this happen but I think its a ground issue with the camera and mic that require more gain to get a good level. With the VideoMic Pro set at 0db and the GH4 set around -12db it’s fine. You won’t hear any noise.

  3. Didier from France says:

    Hi Erik,

    Here in France, I’m not sure that we have the similar audio problem. I can’t here the sound changing when the speed shutter is changing for example as some of you in the US have.
    But yes, i have a little issue : if I put the GH4 on +6db and record sound in a very quiet room, I can hear a very little sound during 2 or 3 seconds just after changing the shutter. But it’s really not a real life recording.

    And I have no problem using my Sennheiser MKE 600 directly in the GH4 or with a Beachtek DXA Connect. Nor with the Senneheiser HF EW100 G2 or G3.
    I also use the Panasonic MV2 and of course no problem (but it’s not the best microphone…)

    Great blog 😉

    Regards

    Didier

  4. Didier from France says:

    I am impatient to read your test 😉

  5. Erik Naso says:

    I received the TRS to TRRS adapter cable and it still has the issue. Unfortunately we will have to wait until Panasonic engineers can figure out how to solve the problem with some microphones like the Rode VideoMic Pro. Sorry. I wish this would have worked.

  6. Erik Naso says:

    I decided to give it one more go. I ordered the Rode SC4 3.5 TRS to TRRS adapter I doubt this is going to make a difference but since it’s made by Rode I know for sure the adapter is what it says it is.

  7. Arya Boustani says:

    Hi Erik,
    Thanks for the info. I just did the test yesterday. I found out that the noise floor resembles situations that the impedance of input is not what it is supposed to be. The extra 4th connector may have caused some sort of bleed from the camera circuitry into the cold connector or may not. But I think it is worth it to try an impedance matching adapter to see what happens. The problem is not solved that way but at least the noise floor can be way down that we don’t notice it at least for 4K shoot. I found 1080 setting makes it louder and even the noise characteristic is a bit different. I use a field mixer and on -12db input setting of GH4, my signal is so hot that I can’t crank up the volume out of my mixer. If I can change the impedance I’m hoping I can make the signal much stronger than the noise floor for either the mixer or the camera. The problem is solutions like this: http://www.amazon.com/Hosa-Line-Match-Xformr-3-5MM/dp/B0002IAJ2O?tag=battleforthew-20
    is for balanced signal but unfortunately if the 4th pole on the 4-pole connector is not to do with making the stereo signal balanced but to do with sending signal to make the mic pattern behaves differently, then the whole sound recording signal path is not great to start with. It seems they only provided the ground connection for the balanced signal from the bottom of the camera that is used for YAGH interface, which means that someone should come up with a GH4 multi-pin to 2 XLR breakout cable.
    By the way, your link for TRRS is for TRRS to TRRS. The TRRS to TRS solution that works for separating the top 3 connector might be this: http://www.amazon.com/StarTech-com-MUYHSMFF-Headset-Splitter-Adapter/dp/B004SP0WAQ/ref=pd_cp_e_3
    or may be this: http://www.bhphotovideo.com/c/product/1048151-REG/rode_sc4_trs_to_trrs_adaptor.html
    or may be this for stereo mic: http://www.kvconnection.com/product-p/km-iphone-micx2.htm
    I’m hoping the last one is a good solution although still we are dealing with the impedance issue.
    Too bad that Panasonic doesn’t spell out the impedance, connectors sequences on the TRRS terminal, and other professional info. I even called them and they didn’t have an idea. They said they will escalate it but I haven’t got anyone contacted me yet.
    I’m getting so frustrated that I may just not reply on the mic input and go with external recorder. I don’t like to pay for another field mixer and find out that the noise is still there in the recorded audio.
    Thanks again.

  8. Clive Arundell says:

    Hi, just thought I’d chip in to add to the confusion ! ;). I’ve just taken delivery of a GH4 and it doesn’t appear to have this audio issue – it is a UK pal version ( I know it has the other settings) I tired it with a standard rode (mono) videomic and it seems fine – I’ve cranked the audio up pretty loud and can only hear background noise of a totally acceptable level – but nothing else? So as some others seem to be suggesting maybe specifc mics are worse than others?

    • Arya Boustani says:

      Hi there,
      I am getting a woosh sound after each word I record with the internal mic as if there is a gate engaged. This is a pain in audio post.
      I made a video of it here: https://www.youtube.com/watch?v=0jbv0oj8gVk
      You may need to listen with decent speakers in a quiet room or with the headphones depending on your ears sensitivity. Anyway, I don’t want to go off topic since this thread is related to the external mic input issues.
      But just wanted to say Panasonic replied that this problem is not for all the units apparently! They asked for my serial number as if there are some units made with slightly different procedure or something! Or may be it is the quality control issue for some batches of production. I don’t know. But I’m just thinking may be the mic input problem also varies. May be the earlier stage of production cameras were different than the later stage. I’m just throwing some possibilities in case some people used the exact microphones and they hear the audible noise even with lowest camera mic input level.

  9. Arya Boustani says:

    I was just reading the connectivity on the 4-pole 1/8″ connectors for iPhone. The ground is the second ring and mic is the sleeve. If Panasonic has followed the same order for the 4th added connector for voltage shifting, therefore that problematic connector is the pole 4 (sleeve) which is equivalent to mic in iPhone. Cables like this:
    http://www.amazon.com/StarTech-com-MUYHSMFF-Headset-Splitter-Adapter/dp/B004SP0WAQ/ref=pd_cp_e_3
    that separate the iPhone mic (4th pole) from the top three (iPhone headphones) can be used and the headphone one has to be used to send unbalanced stereo external mic signal into the GH4 consumer mic input terminal.
    I talked to Panasonic today and they confirmed the mic input is a low impedance kind so the impedance has to be cranked up by the impedance converter in order to avoid getting noise to the camera. I imagine this would work: http://www.amazon.com/Hosa-Line-Match-Xformr-3-5MM/dp/B0002IAJ2O?tag=battleforthew-20
    in conjunction with this: http://www.amazon.com/HOSA-Stereo-3-5-Phone-Male/dp/B000068O5H
    to bring two channels of audio as discrete stereo into mic input of GH4.

  10. Greg Kozlik says:

    Similar issues with GH4

  11. Arturo says:

    Hello Erik, very helpful blog, I’ve a GH4 without buzz issue and I would like to know,how to connect properly a XLR mic, (phantom or not) can you advice in regard good mini plug connector to XLR?
    many thanks!

    • Arya Boustani says:

      Hosa makes very good cables for professional A/V use. This one is probably a good one:
      http://www.amazon.ca/Hosa-Stereo-Dual-XLR3M-feet/dp/B000068OEO/ref=sr_1_4?ie=UTF8&qid=1418939225&sr=8-4&keywords=HOSA+xlr+adapter+1%2F8
      GH4 same as many other DSLRs have unbalanced stereo input so this cable is wired for changing from balanced source to unbalanced receiver. If your mic signal is not hot enough, you may have a lot of noise floor.
      Also the GH4 mic pre-amp is not great. That’s why people like to use an intermediate unit to serve as pre-amp and spits out the stronger unbalanced signal which is much better than a weak unbalanced signal. Then you can crank it up enough a the intermediate unit and reduce the input level of the GH4 to minimize the noise floor and get the best out of the intermediate pre-amp quality.

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