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GH2 Audio Hacks
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  • @Meierhans

    Don't worry: your communication is clear regardless of any technical glitches. :)

    If by "atmo" you mean atmosphere, then I would have some reservations about using a shotgun mic. Using a stereo mic is generally helpful for that.

    But for interviewing and documentaries, I think that the mic is suitable. The quality is quite sufficient for the purpose and it lets you do more with less (and in less time) than just about any other option.

    If you're working from a script, it would really be helpful to have at least one other person assisting you with sound because it's a whole beast unto itself (and the standards are quite different from documentaries and interviews).

    I don't personally think it's worth it to go "in-between" by adding pre-amps, etc. to the GH2 because you go through the GH2's analog to digital converters can't fully defeat the internal pre-amp and and pushing the input gain too much just ends up giving you distortion (like the +20db gain issues I mentioned on the VMP in an earlier post in this thread). Good digital recorders will have better converters and a lower noise level and often provide you with XLR inputs.

    If you're going to upgrade your audio, I suggest having a second person run a digital recorder (like a Zoom, etc.) as opposed to messing about with anything in-between. If you spent an equal amount on both the respective options, the digital recorder alternative would result in a noticeably higher fidelity file.
  • @thepalalias, well maybe you can help with a Job lol, I am in Perth, Australia and looking but not so easy. I am not looking for Music Tech jobs as that would just be a waste of time since its a very thin industry.

    No worry's though I just OK struggling as normal :-), Personal View keeps me sane talking about stuff that I am interested in.
  • Or hire a sound guy ? 90% of GV Cam mic footage is trashed in the mix generally, I wouldn't spend too much on a cam mounted mic (from a dubbing mixers point of view!) Far too many programmes are being delivered every day recorded very badly to the point of not being able to be passed on delivery (CEDAR aint cheap!) radio mics badly placed, badly handled boom recordings and not thinking of where to record basic stuff like interviews (dont sit under the aircon!) ruins some great filmed stuff because production cant be arsed to spend a little more on a sound engineer. It really cant be fixed in the mix - if its a turd - its just going to be a louder turd after the mix.
  • @SoundGH2 I'm afraid I'm not sure what GV Cam is, but I think you're generally preaching to the choir. :) Who was the comment directed at?

    Also, I agree that CEDAR isn't cheap, but there's a whole array of other options from Adobe, Algorithmix, Izotope, Magix, etc. so that people can typically buy the one that fits their price level. What really ends up being important is (as you alluded to at the recording stage) having someone effective there to handle the process. Of course, paying them to there best work will often end up being more of a cost factor than the price of the tools.

    I think we all have stories that illustrate how important using the proper equipment and people for the situation is. But what is "proper" for a given situation varies widely and in many situations a larger team or more equipment isn't practical, and not for the economic reasons. In those situations, having as good a quality as you can get under less than ideal circumstances can be really important. That's why I'm hoping this will be helpful. :)
  • Thanks for the input. I was thinking about the Tascam ixz because it allows you to monitor the audio while recording and to level its output in a way the internal preamps can but set to their absolute minimum. Plus it has an additional mini jack input, so you can add a local battery powered mic for the second stereo channel. I though for 50 € thats quite nice - at least if the name tag still stands for something.
  • @thepalalias

    Hehe aye just grumpy after purchasing 2nd copy of DNS one to save yet another series recorded by a PA for prime time TV. Even a 1 hour basic run through on radio mic placement would save £ks in post trying to polish the proverbial turd - good microphones and radios are now well within reach economically for everyone to afford, its just the back end most production companies cba with sadly. They will happily spend a large section of the budget on grading and virtually nothing on sound acquisition As someone once told me - who leaves a leaves a cinema whistling a two shot? Bad sound kills fantastic picture unfortunately. grump grump lol
  • I can't comment much on the GH2 audio, since I just got my GH2 24 hours ago. But because I am an audio nut on a budget, plus I knew I would be getting this camera sooner or later I got the Zoom H1, and I realize the H3 is the goods, but the H1 really has surprised me. It also has a mini jack input, and the price is about the same at 9000 yen, or 100US. Very light weight, and true X stereo mics. It picks up sounds you didn't even know were there with amazing clarity. I did review the Tascam side by side, but it really seemed to me the Zoom had it beat. Anyways, just my 2 cents. Oh, and I recorded a friends concert with it which was a mix of ambient, techno, african beats, and traditional Japanese folk music, and it all sounded great with no distortion at all.
  • @Meierhans

    Sure thing. I think what @mee just said illustrates a bit of what I was talking about because for not that much more money you've managed to address (at least to varying degrees) the majority of the problems I mentioned instead of just one or two.

    If you really dislike syncing the audio in post, you can actually use most recorders as a pre-amp and monitoring device by setting the output of the digital recorder to the input of the GH2. This gives you a lot of flexibility. You can even use both the GH2 and the digital recorder can recording the same input signal at once and the waveforms will be a lot more similar (and therefore easier to line up visually in post) than if you used difference microphones for each. That is, if you decide the extra fidelity from the digital recorder is worth it (which I think many people would).

    Regarding a direct comparison of those two specific products, I would listen to @mee because I haven't spent a lot of time comparing them recently due to several rather conclusive experiments early on and @mee has recent direct experience.

    As far as Tascam, the name isn't as spotless as it once was in the aftermath of their handling of Nemesys, GigaSampler and GigaStudio, that is to say, the brand and product line that launched software samplers (and after the acquisition by Tascam, one of the first zero latency, surround compatible convolution reverbs). They took a product line that had a market monopoly, allowed it to die, discontinued support completely (shortly after launching the newest version) and in-between let the line fall prey to massive (and repeated) delays, etc., etc. Of course, M-Audio's discontinuation of the MicroTrack line doesn't leave them with a spotless record either, but it's nothing by comparison to what Tascam did...

    Anyway, such politics shouldn't be too big a factor in choosing a relatively cheap product, but I just thought I'd weigh on what the name meant in the circle of software companies I consult for. :)
  • @soundgh2

    Ah, then I can definitely understand feeling grumpy. :) It's really true, both how much money could be saved by properly training the people handling audio acquisition and how frequently the higher ups completely overlook the audio impact. It can be especially frustrating in light of all the research that has been done on the effect audio has on audience/listener response.

    Manfred Clynes (not to be confused with Manfred Klein, the generous font designer) proved years ago that several of the "greatest" performances of the "greatest" classical pieces actually evoked a universal response (as measured in a highly controlled environment through body movement, etc.) REGARDLESS of culture. Just as interestingly, the response was no longer universal if the performance was 2nd tier OR if a 2nd tier composition was used. I wish I had a link ready, but if you're making a film and can put 2 and 2 together, that means you just learned a heck of a lot about reaching your audience.

    Add that to research done during the 90s in computer games, when they did a controlled study of players going through tests with the LucasArts game "Dark Forces" and you see something else interesting. Players going through the game twice without having been told what had been switched cited several improvements: the game was faster, the graphics seemed better, etc. But in reality the ONLY thing that was changed between the two tests was the audio quality.

    Nobuo Uematsu (the composer behind Final Fantasy and one of the 5 most widely performed composers in the industry) said at the Game Developers Conference in 2005 that the music was especially essential to early video games. "Did you ever play any of those games without the music? They were really boring." And the crowd laughed in recognition.

    And finally, what about the famous Academy Awards show where they played the iconic scene from Chariots of Fire of several runners, running alongside one another on the beach? They played it first without the music (very little impact) and the once again with Vangellis soundtrack (suddenly you have the powerful scene that everyone remembered).

    And yet music typically gets a paltry part of the project budget. The Japanese games in recent years had often been especially guilty of this. Keep in mind that the most recent Zelda game is the FIRST to feature a recorded orchestral score in the series and you start to get the idea of the way things had been going.

    Then take a look at the opposite end of the equation. Heavy Rain, a video game that released last year, managed to become one of the top 20 best-selling PS3 games sold to date, one of only 5 that was an original IP. It also had one of the largest audio budgets (thanks to the auteur having previously worked as a composer) and recording sessions at a little place called "Abbey Road".

    The direct emotional impact of things like that has a noticeable effect on the bottom line, and I say that not only as someone working in the music industry and that has done business consulting for several companies, but (just to clarify the reference point) as someone that has grown up consciously addressing these issues since the earliest points of verbal memory with someone that started or ran over 100 and companies (including several Fortune 500s) and was hired at the national level by English, Swedish and U.S. governments to apply that knowledge. In other words, there's no excuse from a business perspective for ignoring how important this issue is, even if someone understand the artistic one.

    In other words, I think we ALL really feel your pain on that one. :)
  • @mee

    Thanks for sharing your experience. I think that may prove helpful to a lot of people.
  • Excellent posts @thepalalias, but you can write a mini guide to enchance the audio recording on the GH2 based on your great experience? They maybe cover the use of the onboard MIC, one external and a bypassed for a external recorder, providing the infamous AGC settings and bitrates... its a ambicious request yes, but im trying :)

    Thx in advance.

    Im currently using a Marantz PMD661 + Rode ntg-2
  • @thepalalias - "If we can't have true lossless compression or high samplerates or bit-depths, etc., etc., I would have to say that there is little be gained by going past 448 kbps for stereo recording..."

    The 448k bitrate in Dolby AC-3 is geared for 5.1-channel recording. For the GH2's stereo encoder, it's overkill, and the excess bits contribute nothing perceptible to the sound quality. If you want to be absolutely certain of getting the most quality out of the Dolby Digital encoder, you could boost its bitrate from the standard 192kbps to 256k, but it's a really steep slope of diminishing returns. As long as it causes no problems with the GH2's audio buffers, there's no harm in wasting a little bitrate.
  • @LPowell I agree completely. I only mentioned "beyond 448kbps" because it's already possible in PTool. :) I did several recordings with the GH2 using 448kbps but then stopped because I could no longer delete video files in camera effectively (since the camera had trouble accessing them since it couldn't play them of course).
  • @heradicattor I'll try to find the time to put one up on my website. Then I'd post a link here. Will let you know when/if gets done. :)
  • @thepalalias

    I tried your setting with AT875R mic and USB Dual Pre. I set the preamp to +20 db input gain and +5 db output gain. BTW it's a cheap preamp. Some people say its preamp is as good as H4n.

    AGC 3: 14 Too much noisy in-camera gain.
    AGC 2: 36 Noticeable noisy in-camera gain.
    AGC 1: 203 Almost no noisy in-camera gain!!!
    AGC 0: 235 No sound.

    I guess the magic number for my audio gears is around 203.

    Then I set AGC 0 to 203. Nice and clean sound. In camera AGC is almost gone when it's quite. Actually I didn't hear any noise. If I need to boost sound, the preamp has more room to boost input and output. There is no need to tweak other AGC settings.

    Great! Thanks!! Woohoo!!!
    Screen shot 2011-11-23 at 4.34.12 AM.png
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  • @StoneBat Glad 203 is working well for you! I`ve been using 203 or 36 exclusively on my last few shoots.
  • Hi @thepalalias Do you have any experience with the Sound Devices MixPre-D?

    It has stereo unbalanced mic level (-36dBu) output to camera over a TA3. It's what we're looking at adding to our setup as everything reads good on paper, but I'd love to hear from someone in the know.

    We want it so we have the option of recording directly to camera, or to recording device (H4n)
  • Hello,
    The mic input has stopped working in my GH2, possibly following the hack.
    Any idea?
  • Get back to factory settings of the firmware and check out again...
  • @itimjim Sorry, I work more with studio sound as opposed to recording for cameras, so I'm not familiar with that particular pre.
  • I have a Roede Stereo VideoMic and I get the same result as @stonebat

    AGC 3: 14 Too much noisy in-camera gain.
    AGC 2: 36 Noticeable noisy in-camera gain.
    AGC 1: 203 Almost no noisy in-camera gain!!!
    AGC 0: 235 No sound.

    The internal mic also sounds better with these settings
    203 and 36 are my settings now Level 2 or 3

    @thepalalias If I set AGC0 to 203 What is a good average for AGC1 between 203 and 36?
  • I wonder if modification of AGC (first two digits hex) affects levels indicators? I've recorded some tests signals on GH2 (AGC1 = 203) fed by line-out from Zoom H2n, loudness set around 25, so the levels indicators were never red. There were no clippings, but some serious distortions occurred. Any thoughts..?

    If you like to use, Im attaching my test signal file.
    Test signal (44 kHz 16-bit).zip
  • @thepalalias

    Did a load of LucasArts early Star Wars Uk recorded stuff way back - fun!

    Sat next to Mr Murch during Cold Mountain and chuckled as he turned off the DFC automation and made everyone play the sound per scene - guess what much better :) Boom ops are so underrated if they're good - makes a story sing ADR - for the artist and us fitting it never has :/
  • @valdi99 I'll look at the WAV file you mentioned, but did you see my earlier comment about the +20dB gain setting on the Rode Video Mic Pro in conjunction with the GH2?

    It was the same phenomenon you described: final output levels were "in the clear" (which was verified using analyzer tools on the PC as opposed to the GH2 meters) but there was very audible distortion in the file.

    The prognosis is that digital gain can be set to attenuate the signal even after it has already clipped or otherwise distorted, and that such distortion seems to happen when the level coming into the mic port is too high. In other words, lowering the digital gain beyond a certain point may actually stop helping because you can no longer keep raising the input gain to compensate without distorting.
  • @soundgh2 Kudos - I have tons of great memories of old LucasArts projects as a young gamer and have enjoyed hearing anecdotes about the production of new projects from friends in recent years. :)