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GH2 Audio Hacks
  • thepalaliasthepalalias
    Update 2013-04-18: The impedance for audio input on the GH2 is apparently 4.7kOm. Thanks for @aenima for testing that!

    In the 30 minutes or so I spent searching for others' information on the audio hacks, I didn't find much so I'm starting a new thread.

    I'm still parsing through data from 12 hours of testing the hacks myself, but I wanted to invite everyone else to post their data too. I'll be posting ideal settings for using the hack to set levels appropriate for interviewing using the onboard mic or the 3 gain settings on a Rode Video Mic Pro shortly with plans to update with settings for another Sony lavalier mic within a week or so.

    All the best,
    Per Lichtman
    VP/Music and Creative, Beyond Belief Music Corporation
    Founder of Pasadena Pulse
  • 302 Replies sorted by
  • disease8disease8

    Hey I know this is resurrecting an old thread but I cannot really understand all the technical jargon here. I just wanted to lower the overall sensitivity of the mic input on the gh2 as it is very hot. I plugged a omni directional lapel mic straight in and even on the lowest setting it is peaking when I speak loudly. What setting would I have to use to lower the overall volume in the 4 agc stage hack section of Ptool?

    Also, it definitely

  • FieelFieel

    @thepalalias Thank you very much for the swift answer !

  • thepalaliasthepalalias

    @Fieel The audiohack is already included in any recent Driftwood patch unless specifically mentioned otherwise. This includes Moon T8.

  • FieelFieel

    I'm still missing a basic concept: can i safely add an audiohack to my already hacked Moon T8 GH2?

  • MirrorManMirrorMan

    @thepalalias Thanks for the additional tests. I think the Primo/GH2 combo holds up really well and this quality would not be possible without your audio settings. If anything, the capsules are maybe too sensitive for the current AGC settings. As you heard in very quiet environments I could not go above +2 without it hanging in the red and the cameras compression being too noticeable (for me). So for a noisy urban environments a really low sensitivity will be good to have (I'll test it soon). Regardless, I'm so impressed I went ahead and ordered a second pair of Primos to build my on camera 'dream mic', an ultra-lightweight high sensitivity ambient stereo mic. Its basically the two capsules mounted on a cheap shockmount rig turned sideways with a styrofoam baffle in between. For wind protection, I used the ends of two foam windscreens and covered it with a stocking. I'll need sew up a furry soon for heavy wind conditions, but so far this works great. I've also set my Drewnet T9 audio setting to 320kbps.

    Coincidentally (or not) these are the same capsules used in the 3Dio 'free space' binaural mics (http://3diosound.com/). I've tried that one. Its nice but I'm not a big fan of binaural sound for video and the rig is really bulky. My mic weighs about an once, doesn't need batteries and cost me less than $40.

    P1180642.JPG
    1200 x 801 - 225K
  • thepalaliasthepalalias

    @MirrorMan I wanted to see how your test handled a lot of processing. So I took it through the discontinued Abbey Road RS127 Rack Plug-In, VSL Exciter, Nebula libraries (AlexB's Modern Flagship Console, CDSoundMaster Ampex and Tape Booster Plus), Slate's Virtual Console 2.0 and the VSL Limiter (which basically doesn't limit after the first 20 seconds). This gives the recording a much more "hyped" sound, with less of an emphasis on the bass and low-mids.

    Here's your original audio, without additional processing. http://perlichtman.com/media/2015/tests/optic-influx/Optic%20Influx%20-%20DRY.wav

    Here's the "hyped" version. http://perlichtman.com/media/2015/tests/optic-influx/Optic%20Influx%20-%20Primo%20EM172%20Audio%20Test%202015-07-03%20a_4.wav

    Basically, I wanted to see how the microphone/codec combination would work in post for people that wanted less warm sound. I think it held up well. Thoughts?

  • thepalaliasthepalalias

    @MirrorMan I think that's the coolest demonstration I've heard anyone do with the Pasadena Pulse Audio settings so far. Kudos. :) I want to try something with the MP4 real quick - I'll post again shortly.

  • MirrorManMirrorMan

    I'm posting the outcome from some recent audio tests I made with a DIY spaced omni configuration using Primo EM172 capsules. For those who don't know, these capsules are probably the best deal on the planet. Considering they cost about $10 per capsule, the quality is amazing. They have lower noise and higher sensitivity than the DPA 4060 mini mics. I ordered my capsules online from http://micbooster.com/

    For this video the mics were plugged directly into the GH2 and positioned just below the camera in an A-B 'spaced omni' configuration for an optimum stereo image (see photos at the end of the video). All clips are straight out of the camera. AGC was always set to '2' using Per Lichtman's Pasadena Pulse audio settings. No post-processing has been done. Please use good headphones of speakers to listen.

  • treibholtztreibholtz

    @thepalalias i try to use a minor step between levels

  • treibholtztreibholtz

    i use: ACG O / 203 (-72 dBfs) very good ACG 1 / 192 (-70 dBfs) very good ACG 2 / 176 (-67 dBfs) good ACG 3 / 160 (-60 dBfs) same hiss

  • bananaramabananarama

    Hi !

    thanks for this topic !

    Do you or any knows if, as I don't use audio at all, I do music videos only, I can disable totaly the audio or reduce the stream to 1 on the camera or by modifying the hack by editing them ?

    this should help stability a little

    thx !

  • nirolifeactionnirolifeaction

    Hi, that has solved the issue : http://www.ebay.com/itm/3-5MM-HEADPHONE-JACK-AUDIO-NOISE-FILTER-GROUND-LOOP-ISOLATOR-1-8-HUM-SUPPRESSOR-/281170068118

    many thanks for your help

  • nirolifeactionnirolifeaction

    Many thanks for writing your experience with the ART USB Dual Pre. When I plug it into the socket, there is no noise. I can not operate both via V-Mount Battery, either ART or Lilliput. It's really frustrating.

  • JiveJive

    I tested the ART USB Dual Pre and experienced the humming issue as well. I've since returned it and don't remember if it was isolated to when it was powered by battery or plugged in.

    It did seem to be a grounding issue because touching the preamp's outer housing would affect the hum.

  • matt_gh2matt_gh2

    Cool - Reminds me of how plugging in (vs battery only) can cause problems for some electronics.

  • nirolifeactionnirolifeaction

    If I do not operate the monitor via the Lanparte Battery Pinch, but on his own power supply, then there is no humming. I read something about a ground loop, but do not understand properly how it can come to it.

  • nirolifeactionnirolifeaction

    Maybe it has to do with the ART's 1/4" outs, I found something: "A final issue to consider is getting your camera an impedance that it likes. I've had a maddening issue with broadband noise and it seems to be related to impedance, 600 Ohms is noisy and 150 - 200 Ohms is quiet. The ART's headphone output impedance is quite low (50 Ohms), but the 1/4" outs are 600 Ohms, so simply padding their output may not be sufficient to get a good result."

    Maybe a Sescom cable is the solution.

  • matt_gh2matt_gh2

    I'm not super technical so I'm not sure cause, but I bet a few of the more technically knowledgeable guys on this site will chime in with answer/solution after turkey day.

  • nirolifeactionnirolifeaction

    Thank you for your answer. In this way I was able to find the 'ART USB DualPreamp' as a source of interference. First I tested with field monitor only, as you suggested. There is no humming with in camera mic, i used AGC-level 3 - 128. Than, with NTG2 plugged directly into the GH2, without preamp, it sounds good too. As third try I changed the NTG2 with the H4N as external mic plugged into camera, same result, clear sound without humming while video monitoring. I set the mic-level to 1/ 235, checked all cables and tried with the preamp, first the NTG2 and then the H4N . . . strong humming. I changed the XLR-cables, used another power source for the preamp. When I turned off the monitor, clear sound. Too bad! Maybe we'll find out why the preamp disturbs. Probably the device is of low quality?

  • matt_gh2matt_gh2

    @nirolifeaction A few random thoughts here: Have you removed all audio equipment and tested with field monitor only? If you do this test and audio from in camera mic is still humming, then you know its definitely your monitor setup.

    Maybe try a different hdmi cable. Also maybe try taping your cables in place to make sure they don't wiggle around in the socket/plug area.

    The first thing I would check is to make sure all cables are FULLY plugged in, because halfway plugged-in cables often create a humming sound. (sometimes plugs need a bit of a push even though you think they're in - don't force it, but just another light push on all cable connections for monitor and audio gear might do the trick).

  • nirolifeactionnirolifeaction

    Hi I have read everything but found nothing to solve the problem. Maybe I'm right here and find help. my setup is a NTG2 with XLR to ART USBDualPre connected with the GH2, AGC 0 - 235 / AGC 1 - 203. Everything worked fine until I wanted to connect a fieldmonitor via HDMI. Whenever I connect the HDMI cable with the GH2 for video monitoring, the sound gets terrible, humming and bad disturbin noise. I've tried many things but nothing. It must be possible to connect an external microphone and a monitor for liveview, or am I totally wrong?

    Hopefully someone can help me, excuse my english;).

    greetings

  • valdi99valdi99

    I recently bought Tascam DR-60D to I use with my GH2 (and stereo mic based on and EM172 capsules) and I am VERY pleased with it. Great quality, juicy & clear, rich sound, no noise even at highest gain. This setup fits my GH2 perfectly, attached just underneath to the tripod socket.

  • thepalaliasthepalalias

    @LALisa Looking forward to hearing your experiences with it. Keep posting!

  • LALisaLALisa

    I want to try this setup for external AC supply for 9 volt battery...

    Tronix ACA1 Universal AC DC Adapter by Tronix http://www.amazon.com/Tronix-ACA1-Universal-AC-Adapter/dp/B000G20YOO/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=34MJN2L9TSYJM&coliid=I1TPZ1TD45N955

    Maximal Power 9-Volt Li-ion 550mAh Rechargeable Battery by Maximal Power http://www.amazon.com/Maximal-Power-9-Volt-Rechargeable-Battery/dp/B0051WZ516/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=34MJN2L9TSYJM&coliid=I1Z02MAZMBTSG3

  • LALisaLALisa

    Sorry I am just getting back to the issue of making quality audio to the GH2... I got the Beachtkek DXA-2T to work with my GH2. Monitoring is a big issue...

    I also have the BeachTek DXA-5DA working very well with my GH3 for field recordings. I have not tried using the DXA-5DA with the GH2 yet...

    I expect the BeackTek DXA-5DA to work very well GH2... This unit eats 9 volt batteries...the plus side to this device is to be able to monitor the audio input to the GH2... I am looking into 9 volt battery AC adapter now...

    What I especially like about the BeachTek devices is to be able to plug line level or microphone levels in as well as other line level devices in...

    Beachtkek DXA-2T http://www.amazon.com/BeachTek-Universal-Adapter-Compact-Camcorders/dp/B0039QWR5I/ref=sr_1_1?s=electronics&ie=UTF8&qid=1371047896&sr=1-1&keywords=beachtek+dxa-2t

    BeachTek DXA-5DA http://www.amazon.com/BeachTek-DXA-5Da-Passive-Adapter-Camcorders/dp/B0039QWR7Q/ref=sr_1_3?s=electronics&ie=UTF8&qid=1371047896&sr=1-3&keywords=beachtek+dxa-2t

    I have not tried the BeachTek DXA-SLR Dual XLR Audio Adapter with Built-in Preamplifiers and Phantom Power for DSLR Cameras with Mic Jack http://www.amazon.com/BeachTek-DXA-SLR-Adapter-Preamplifiers-Phantom/dp/B003E3RK26/ref=sr_1_2?s=electronics&ie=UTF8&qid=1371047896&sr=1-2&keywords=beachtek+dxa-2t

    This is a better build with sturdy die-cast aluminum chassis Camera mounting bolt Record/Playback monitor AGC Disable feature Headphone jack

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