DVX100B Adobe Audition and Crappy Audio

C

ChipThome

Well-known member
I have two DVXs now and both give me audio that looks like this is Adobe Audition

I have run through everything I can think of, and what I was able to find in the Owners manuals and have not found the setting that will give me a "normal" waveform when the audio is extracted.

As you can see, the upper half of the waveform on both the left and right channels, appears to be "subdued" or "compressed" where the lower half is "running free".

I have NEVER had this come from any of my other cameras, or board feeds, and am completely stumped. Tonight I took my laptop and asked a couple of guys far more familiar with audio, and they were stumped too.

What can I change in my camera or settings, to get the upper half of the waveform to resemble the lower halfs ??
 

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WHERE did the audio come from? HOW did it get into the camcorder(s)? WHAT is the audio? How did you conduct the test?

Are you only complaining about what the waveform looks like? Or do you have some issue with how it actualy sounds? Note that it is not uncommon to see asymmetrical waveforms.
 
Hi Richard,

The audio is an representative sample of what I have gotten the last several times out. All have been live band performances (loud). All were shot on one or the other of my DVXs and captured via a Panny 320. Last night I shot with ALC "Off" and made no difference.

All were using the Internal Mic, with both Mic 1 and 2 set to Int.

And the audio quality, sucks, am sorry to say.

When I import a video clip into Audition, this is how the waveform looks. This also is peculiar to my DVXs, and have not ever gotten this from any audio from my other cameras that have used internal or external mics or board feeds, for the audio source.

Last night I took my laptop with me and asked a guy who uses Audition extensively in his job. He is one of the people who is also stumped at what may cause this. His best guess was there had to be some "pad" set somewhere giving me this audio.
 
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The easy answer to this conundrum is to stop shooting with the internal mic. The only time I have seen usable audio going to the DVX or any camera directly is through a mixer. Most of the time, its best to do what has been done since the dawn of "talkies" and record to an external source then sync your audio later. I have found that you can get great sound by just recording directly to a laptop.

Best of Luck!
 
Lousy audio from the internal mikes is par for the course.

OTOH, I can't SEE anything in your picture of the waveform that would predict bad audio. I have edited plenty of tracks that had waveforms even more asymmetrical than yours and there was nothing wrong with them. There are lots of sources, both instrumental and human, that produce dramatically asymmetrical waveforms that are perfectly normal.

If you have bad sound, I would NOT immediately assume that the asymmetrical waveform was implicated (or even symptomatic). It may just be a coincidence. Perhaps it is time to post a short uncompressed (WAV, etc.) sample somewhere where we can hear it.
 
Here is one song from Saturday night. That night ALC was still on, but turning it off made no difference in the waveform on Sunday's shooting. Both nights, the camera was set to -60 for both mics and the audio dials set at about 2.

I have uploaded some black video with the audio from this song. I went to the preset in Audition 3 to "Normalize to -1" and this is how it looks in Audition 3. When I get the "video is rendered" email, I will attach a link to it. Vimeo says about 30 minutes.

In the image you see the bottom half of the waveform is extended down toward that -1 while the top half, is stopped around the -6 or so range, because of the difference in the two halves. I am ending up with much quieter audio than I ever have in the past, because of this anomaly.
 

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ChipThome said:
have not ever gotten this from any audio from my other cameras that have used internal or external mics or board feeds, for the audio source.
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Have you tried a board feed into the DVX? (at a proper level). If you're limited to two channels, the minimum IMHO to get a decent band recording would be one channel (mono) out of the board and the other from an external mike. Then mix and add some stereo effects to taste.

Better still is a stereo mix from the board to the camera line inputs plus a stereo ambience recorded to something like an H4 (or vice versa).
 
I don't see or hear anything particularly wrong with your audio recording. The micing seems somewhat hollow and distant-sounding, but I don't see anything particularly abnormal with the waveform. What does the waveform look like when recorded on something else? If you really think something is wrong, start applying the standard differential diagnosis techniques. I really think you are barking up the wrong tree here. Asymmetrical waveforms are normal.
 
...and I gotta add, when using a good quality external mic or a good line signal, the DVX preamps and converters are really pretty good. Not just "good" technically - they have a nice clarity, punch & character.

I used the DVX for some home-brew guitar demo stuff, with a Sure 57 and various condensers. Thought I was recording scratch tracks, but it all sounded great & mixed really well in Pro Tools.

But recording live acts with the on-camera mic (what's the symbol for severe shuddering???) It's going to be weak, and the sound will change every time you move.

Your optimal minimum should be 4 tracks - the board outs, and two identical, good-quality mics (like large diaghragm condensers) getting the overall room sound - high enough up that they don't capture individual audience voices. (Years back, we got great results taping PZM mics to the back wall of the club). Or find a friend with a decent Pro Tools or logic laptop rig and get all the tracks you can.

With all the multi track shareware and chinese mics out there, you should be able to do this with a laptop and some cables/adapters.
 
You should do one of a few things.

1. understand that audio recorded from the internal mics is not good for professional use.

2. set up the camera to record audio from the in house mixer or your own mixer.

3. or use an external recorder for your main audio and your audio on camera as reference audio.

Good luck.
 
Thanks guys,

My preferred choice is as has been suggested, a stereo external mic, and a board feed mixed in post. The on cam mic audio, we have typically used that as "last resort" in case we have failures in our other audio tracks.

I wasn't expecting great audio, but at least "home movie" caliber from the DVX. My GS500s actually do a better job than the DVXs are at this time, with the on board mics.

Last night I set the DVX up in front of my radio and played it load, for a radio, and recorded a minute to compare that level, to the bar band level I had posted before. In this case, the waveform is as I have always experienced, balanced somewhat equally, upper and lower.

Now I am really confused, as I was expecting the same image of the waveform, but now get one "normal" appearing.
 

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ChipThome said:
Now I am really confused, as I was expecting the same image of the waveform, but now get one "normal" appearing.
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If this were RF, I would have suggested the 'strange' waveform 'look', may be due to multipath, which can give rise to incredibly 'strange' waveforms, due a number of phenomena, such as phase cancalations, waveguide effects, response modals of the environment, etc.

The other idea was that your unit is defective, and some how the internal amp has been biased 'up' such that the postive going voltates are hitting some nonlinear range of the amplifier.

But with your last example, where the look of the envelope looks somewhat symetric, perhaps what you are seeing is a characteristic of the recording room, the bar.
 
Chip:

Worry less about the waveform and more about how it sounds. The final waveform of a mixture of frequencies such as you find in music can be very complex and there's nothing writ on granite that says complex waveforms are symmetical, it all depends on how the multitude of frequencies mixing together at some given instant sum. Be more concerned with how it sounds. If it sounds good on a proper monitoring system, don't worry about the beauty of the waveform picture, you're the only one who will see it. If it sounds bad, then figure out what went wrong and how to prevent it next time.
 
ChipThome said:
Last night I set the DVX up in front of my radio and played it load, for a radio, and recorded a minute to compare that level, to the bar band level I had posted before. In this case, the waveform is as I have always experienced, balanced somewhat equally, upper and lower.

Now I am really confused, as I was expecting the same image of the waveform, but now get one "normal" appearing.
Click to expand...

They process the heck out audio waveforms before broadcasting them, so it does not seem surprising at all that you are seeing more symmetrical waveforms. Good work on the differential diagnosis experiment.

Whatever issues you have with how your audio SOUNDS has nothing to do with the waveform. It has very much to do with the mic(s) and location(s).
 
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