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GH2 Audio Hacks
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  • i know... but most of work that i do, i not have enought time to record a separate track, when i can, i have a sound boy, with his audio recorder. I just saw some audio recorder like H4n, but in past with hv30 and SD700 i had a satisfied audio in my video, and i would found something like this.
  • @madrenderman

    So you're using a 2 ring adapter, and you've tried the updated values I posted earlier with the version 1.0 firmware? Or are you trying it with the unhacked version 1.1. firmware? I'm planning on trying 1.1 for the first time today and (depending on the results) to work with refining the values more today.
  • @madrenderman Personally I have not had any experience with the issue you mentioned, with it starting and stopping recordings. Normally I would get silence if it disconnected and things like that, but not this other issue.

    How hot is the signal and what's causing the spikes?
  • @thepalias
    i found problem, is the adapter, i tested with another adapter from my friend, and problem is gone.
  • @madrenderman Great, glad to hear it.
  • "What i really would love to see too is a headphone out over the AVout while recording (of course)."

    Ditto that.
    The fact that it's there for playback and not recording means it's in the firmware.
    I've taken the RCA and run them into a set of headphones with an adapter. It works, but it's not loud. But works is better than "not works." :)
  • and a small headphone pre will fix it.
    Got my GH2, impressive cam, still play arround with basic functions.
    Tested the Rode Videomic Pro with a G2 wireless, nice, really nice, not noisy and really ok sounding.
  • @IEBA1 "I've taken the RCA and run them into a set of headphones with an adapter".
    What do you mean by that, can you be a bit more precise?
  • @Gameb You can get a dual RCA female to 1/8 inch stereo (two ring) female adapter or cable. Some of the most popular ones are made by Hosa and they can be bought online or at stores like RadioShack.
  • Is it also possible to completely disable audio recording? It would be great to save some space and also datarate for high bitrate shots e.g. slomo - no need for audio....

  • You'll save hardly anything by disabling audio. The audio bit rate is very low compared to the video bit rate.

  • Actually I'm beginning to work on a patch for timelapses and in this very particular case (bitrates much smaller than stock) the audio bitrate might still eat between 5-10% of the total bitrate... I really wouldn't mind disabling it or being able to set it to something like 128kbps or even smaller since I'm going to trash it anyway... :|

  • Hi to all, I tested the settings AGC 3: 14 AGC 2: 36 AGC 1: 203 AGC 0: 203

    on a field mixer, which provides +6db/-34db/-54db output. (This mono mixer is from a long defunct german company called SIE and was developed for having more accessible functions than the SQN. LED´s for levels, pregains accessible by switches, three outputs, two headphone jacks for 6,3/3,5mm) I used the onboard sine generator and limiter of the mixer for testing, to evaluate headroom. Overshoots do not exceed 1db with this limiter. Output was set to -34dB Audio bitrate set to 348 using the spanMyBitchUp settings. So as far as I understand the hacked settings, there is no difference between ACG 0 and ACG1? Because in both settings, with 0dB 1 kHz signal, I get around -9db headroom in GH2... Which is perfect No audible distortion. BUT: Haven´t tested lower levels yet, but with hacked setting, are ACG0 and ACG1 identical? Or does the GH2´s limiter start working at around - 9 db, independend of gain? All the best, Frame

  • Hi @Frame,

    Looks like you mixed up the settings slightly, at least if you're trying to emulate the ones I mentioned initially. :) Here they are.

    14 AGC 3 36 AGC 2 203 AGC 1 235 AGC 0

    In other words, 235 will get you a lower level than 203. It is possible that this is just digital attenuation after the fact and you might not gain anything by it, but the level should definitely show up as different for AGC 1 and AGC 0.

  • I just use a 2.5->3.5, then 3.5->dual XLRs using a Sennheiser M66 and another microphone.

    The 3.5->XLR has dual XLRs(left & right) and it seperates the tracks into stereo. So you can have two microphones. This give you two tracks high quality audio recording.

  • @re9d do you have any pix of this rig setup? sounds interesting.

  • Hello guys, I have made some tests for microphone level settings today- with interesting results. I had unfortunatelly no time yet to check the sound quality. I've been manipulating Threshold values and found one setting with higher sensitivity, one setting with lower sensitivity than standard GH2 mic level, respectively (see attachment). I will be checking again more when I get on vacations.... too much work right now :(

    Micro sensitivity.txt
    589B
  • @SisterCities, the original question was going to be, 'why are you going from the zoom h4n(or what ever portable recorder) to the GH2?

    I believe that Vitality's higher audio bitrate is high quality than portable recorders(especially what comes out of their 3.5 line out) and really what bothers me is this way of doing things is the 'Canon DSLR way'.

    XLR is essentially mono and the jack is stereo, so that give you two channels. I've moved on to using a mix of mics for this set up -- two lavaliers -- shotgun with a handheld for interviews --or just patching into the a audio board where they provide a mix for multiple microphones and bus them into a stereo mix down.

    Wish I knew more about how to apply some of the new features concerning audio... i.e. Audio Buffer Size.

    Little hint though... I personally always reset the AGC settings, starting at zero, with the highest at twelve. Boosting the audio more than that is flirting with disaster and really you're probably doing something else wrong if you're turning up the volume.

  • @re9d it may be much higher bitrate, but the quality of the analogue-to-digital converters on the GH2's board will be likely of a much lower quality compared to a specialist sound recorder's. Whether the quality is acceptable or not is subjective.

  • @Ptchaw, well they were testing the sound quality by going from a: XLR mic -> Zoom h4n ->3.5 -> 2.5 input on the Gh2.

    I just suggested that they should be going strait from an XLR source to properly test or even to have the best quality.

    idk in concern to Zooms and other portable recording devices... I think the GH2 might actually be better(with the hack)

  • Just did some audio tests with a Sennheiser K6 Shotgun with Rycote Furry Windsock which i use as an outdoor interview mic at 2ft mouth distance and Mic level 2 (AGC setting 1 below) is a perfect level with very low noise floor.

    I also tried a Sennheiser ME2 lav, and it works well at Mic Level 2 for strong voices or Mic level 3 for softer voices.

    For the internal mic, Mic Level 3 has no pumping and is good for an ambiance recording or close by (within 3ft) interview.

    These all imported into Sony Vegas pro at with peaks at -6db, no audible distortion or AGC pumping. The noise floor is actually quieter than my H4n with the same mics.

    Only have the in-camera level meters to sort out now, the low end 1-5 is ok but need to extend it so 6-10 eventual showing red last 2 segments.

    These were the settings @thepalalias supplied

       14 AGC 3
       36 AGC 2
       203 AGC 1
       235 AGC 0
    

    Wish the same thing was available for the GH1.....VK ????

  • @Rambo

    I may be late responding, but I'm glad that the AGC 1 setting worked well for you. :) Were you using Firmware 1.0 or 1.1, by the way?

    Someone earlier in the thread mentioned that external mic performance might be different in the new firmware but I was unclear if that meant "different default AGC values" or "different AGC behavior in the new version". I may have to test it when work slows down.

  • New FW version 1.1. This is very very usable for when i don't want to use my H4n, actually it sounds lower noise than the H4n using the same mics. The 2.5mm socket connection is the risky part. I would be relying on the level meters to be sure the connections are solid.

  • @Rambo, that's really the only reason I grudgingly use an external audio recorder (DR100 MK2). The 2.5mm jack and cheap adapters are really the weak link in the chain. I've had issues with an adapter that was causing static. I noticed it from the jumping level meters on the LCD, but there was no way to diagnose it without a headphone jack.

    Adding an external recorder makes my setup far less mobile, but at least I can monitor my audio and have a backup. A headphone jack and more granular control of the audio levels are 2 of my main wishes for the GH3 (and with such features on Nikon's D800 and Canon's 5DMK3, it may not be too much of a fantasy).

  • I grudgingly use an external audio recorder (DR100 MK2).

    How are preamps in MK2?