GH2 Clean (low noise) audio possible with GH2?

RieniO

RieniO

Well-known member
Am now using that Panasonic mike on top of the GH2 but I find the result rather noisy compared to for example the AF101. Is this noise the result of the hardware/codec inside the GH2 or is it produced by the microphone? What can I do to achieve cleaner audio? Purchase the Rode pro video mike or an XLR adapter with built-in pre-amp?
 
For about $100 you can buy a Zoom H2. The external audio will be of high quality, and you can use the zoom as a mic to plug into to your camcorder. Some of the Olympus cameras have 16 bit audio, and the sound is decent, but 24 bit is the modern standard (although 20 bit would be fine, they don't make cheap 20 bit recorders).
 
I already have the Zoom and the Tascam 100. The inputs of the Zoom are much too insensitive for what I do, the Tascam is a bit better but still can't be compared to for example the XLR inputs of the AF101 or HMC151... I just ordered the Beachtek DSLR box, it has pre-amps and I hope they are good enough for what I need.
 
Here is an interview I shot a few weeks ago using a Sennheiser G3 UHF wireless handheld mic fed directly in to my GH-2. This was shot in the quietest spot I could find in a busy hotel lobby, where I had roughly 1 minute to set-up before I had to start shooting. The audio has been compressed slightly to even out the volume, but otherwise this is a sample of the type of sound you can get from the GH-2. ( I have better audio gear, but nothing as portable as this Sennheiser G3 UHF mic set-up ) If I remember correctly the handheld mic was set to -12 dB on it's menu, and the receiver was set to -6 dB, which seemed to produce the cleanest signal. Lens was a Zeiss ZF 50mm /f1.4 set to f/2.4, shot at 1080 24P, ISO was 320, color balance was 3000 K ( dim tungsten hallway lighting )

Micheal Vonn talks about E-Health, HIV and Privacy
 
RieniO said:
I already have the Zoom and the Tascam 100. The inputs of the Zoom are much too insensitive for what I do, the Tascam is a bit better but still can't be compared to for example the XLR inputs of the AF101 or HMC151... I just ordered the Beachtek DSLR box, it has pre-amps and I hope they are good enough for what I need.
Click to expand...
Would love to hear what you think of the Beachtek DXA after you try it out.
 
TheDingo said:
Here is an interview I shot a few weeks ago using a Sennheiser G3 UHF wireless handheld mic fed directly in to my GH-2. This was shot in the quietest spot I could find in a busy hotel lobby, where I had roughly 1 minute to set-up before I had to start shooting. The audio has been compressed slightly to even out the volume, but otherwise this is a sample of the type of sound you can get from the GH-2. ( I have better audio gear, but nothing as portable as this Sennheiser G3 UHF mic set-up ) If I remember correctly the handheld mic was set to -12 dB on it's menu, and the receiver was set to -6 dB, which seemed to produce the cleanest signal. Lens was a Zeiss ZF 50mm /f1.4 set to f/2.4, shot at 1080 24P, ISO was 320, color balance was 3000 K ( dim tungsten hallway lighting )

Micheal Vonn talks about E-Health, HIV and Privacy
Click to expand...

I thought that sounded pretty good.
 
Do you have the H2 or the H4? The H2 can be modded to a decent sounding 4 track recorder, but it is, of course, line in. The advantage is that it has four decent mics built in to a compact frame with pattern adjustment, and so on. I prefer the sound to the H4, but many opt for the H4 for the preamps, which aren't great. The AF101, AFAIK, is 16 bit audio (hey, 35 year old technology, that is so cool), which is still a limitation as far as post processing. When I don't bring "the truck", I'm using the Tascam DR 680 which has excellent preamps, and you can use the onboard digital mixer to feed your cam if you really want in-cam sound. The pres/AD section on the 680 compares favorably to some of the very expensive gear, there is really only a tiny difference. The even smaller difference is in the noise floor would only be apparent in a super quiet recording studio.
OTOH, a lot of people are very happy with Rode video mics. For me, there is just an inherent limitation in "in-cam" sound, if you really work, you can get decent results in 16 bit, but most cams offer heavily compressed sound. The GH2 sound is heavily modulated, as well, owing to the AGC. You can use a pilot tone to defeat it, but it still will be on the verge of cheesy, soundwise, unless the new hack frees up the bitrate. If you just need preamps, there are now some very nice low cost options, such as the Mackie 2-channel.
 
I have the H4 and the preamps of that are useless, if it has any. Maybe nice for recording heavy metal concerts but even for normal human dialogs you'll have to put it on 10. I never tried the built in mikes, I used it with external XLR mikes only. Another thing I don't like about the H4 is the sync drift, I suspect about one frame per 5 minutes. The Tascam 100 doesn't have that problem and the preamps are a bit better but not fantastic. The reason I want to record in-cam though is that when working with two cams, all the syncing on the timeline became too time consuming. Ok I admit I never bothered to try Plural Eyes.

The Beachtek DSLR DXA should arrive in a few days, I will do some testing. If the pre-amps are as good as they claim then I can always connect it to my Tascam if I still think the in-cam sound of the GH2 isn't good enough.

Did anybody notice that in the GH1 and GH2 the audio is always 2 frames ahead of the video? It's not a problem for me, it's very easy to solve but it would be nice if Panasonic would have fixed this in the camera, shouldn't be too hard. Still I love the GH2, am shooting with two now and selling my AF101 because I'm not using it anymore.
 
Most cameras have a tiny offset for the audio, because the manufacturer assumes that there will a few feet to travel to the microphone. Ideally, the offset, or delay, should be programmed into the distance scale of the lens, however most cams just use a tiny delay. On my Panasonic cams the delay is way less than a frame, just a few milliseconds, so there is something going on with your audio, I think. However, with certain hacked firmwares, I have occasionally experienced a delay of a few frames, when the bitrate was set pretty high.
But I am assuming that the GH2, you have not tried the hacked firmware? Then there is something going on perhaps with your NLE. Try dumping it into a different NLE and see if the result is the same, or re-transfer the files using a different card reader. There should not be a lag of several frames. Even using an external source for the mic, and assuming it uses the cheap signal path of outputtung the feed from the converters, which introduces say a one millisecond delay, that is way less than a frame. However, if you are using effects, on an external source, that might do it. Try just using the cams internal mics and see if there is still a delay. If the problem persists, that seems like a service item, but it is funny that it affects both cams in the same way, so I would look first at the other possibilities.
Preamps: The Fostex FR2-LE and the DR 680 preamps and AD converters are excellent. The 680's are a tiny bit more transparent, but you can Mod the Fostex input stage and get very good results. Out of the box, it is just fine, however. The Fostex main problem is the noisy headphone jack, which when you first use the machine is a little nerve racking, but the recorded sound is excellent.
The built in mics of the H2 are decent, but maybe not what you want. It is a handy item, small enough to put on a boom, four mics that can be used in different patterns, on a tabletop for an interview.
Drift: Fostex FR2-LE and RME interfaces, very little drift; Tascam DR 680, very slight drift. Assuming the clocks on your cams are accurate, of course. RME have very good clocks.
 
The 2 frame difference may be caused by FCP, that's what I use for the editing. I've always had the audio 2 frames ahead on video also when editing DV and HDV. But amazingly when editing AF101 footage, the audio is total in-sync, frame accurate with the video. I'll keep my Zoom H4 and Tascam 100 for a while in case the Beachtek doesn't do what I need it to do.
 
woodcarver said:
Would love to hear what you think of the Beachtek DXA after you try it out.
Click to expand...

I've been using the Beachtek DXA DSLR box for a few weeks now and I love it, it provided me with the best audio since working with DSLR cams and even the AF100. The trick is to put the input level of the GH2 on "one" to eliminate the GH2 noise as much as possible, then you put the gain switches of the Beachtek on high and mike level on full. In that way you bring down the GH2 noise level to acceptable level. Maybe it's even possible to get better results with putting the GH2 audio input on 2 or higher but I'm happy with the above settings for now. So no more using external recorders with useless pre-amps like the Zoom and Tascam. The only disadvantage of the Beachtek is that it uses a lot of power, we're using rechargeble 9V batteries and had to swap them about every 2 hours. We'll try to find higher capacity batteries or build some solution ourselves to put a bunch of batteries in parallel position or use a 9v mains convertor. I guess most power is used by the pre-amps and 48v powering of the mikes, both the Zoom and Tascam use a lot of power too.

I guess the Juicedlink boxes are similar to the Beachtek boxes, as long as they have pre-amps (in other words, they are active) they should be proper solutions as well.
 
RieniO said:
I've been using the Beachtek DXA DSLR box for a few weeks now and I love it, it provided me with the best audio since working with DSLR cams and even the AF100. The trick is to put the input level of the GH2 on "one" to eliminate the GH2 noise as much as possible, then you put the gain switches of the Beachtek on high and mike level on full. In that way you bring down the GH2 noise level to acceptable level. Maybe it's even possible to get better results with putting the GH2 audio input on 2 or higher but I'm happy with the above settings for now. So no more using external recorders with useless pre-amps like the Zoom and Tascam. The only disadvantage of the Beachtek is that it uses a lot of power, we're using rechargeble 9V batteries and had to swap them about every 2 hours. We'll try to find higher capacity batteries or build some solution ourselves to put a bunch of batteries in parallel position or use a 9v mains convertor. I guess most power is used by the pre-amps and 48v powering of the mikes, both the Zoom and Tascam use a lot of power too.

I guess the Juicedlink boxes are similar to the Beachtek boxes, as long as they have pre-amps (in other words, they are active) they should be proper solutions as well.
Click to expand...

What about the auto-compression on the GH2? Wouldn't you rather have an independent recorder that can do a higher bitrate and depth (96kHz 24bit) than the onboard GH2 with auto-gain adjustments that cannot be turned off? I ask because I started a thread asking about this topic, except I am actually looking for an external recorder.
 
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