audio import digital noise

mattadamsapple

mattadamsapple

Well-known member
Hey guys/gals,

When I play my mini dv tapes through my speakers, I have no audio issues but when I import it the footage into FCP 6 I get very minor digital noise. It's kind of sounds like a high pitched static that goes on and off. It's not super loud but it's distracting nonetheless. Has anyone else had this issue??

I can upload a bit of it if anyone could be of help, Id really appreciate it.. I shot in 24pa and didn't use an external mic/ imported at 29.97 48 khz Thanks!
 
Thanks for the respose Noah. That's the thing. There's nothing in the mix except from the sound on that tape. It's really strange. It could be a system configuration issue. I'm always getting a little bit of digital noise through my head phones and my speakers pick up radio waves as soon as my system goes to sleep.

Before I owned the hxx, i hired someone to follow me around (camera dude had a dvx 100) on the trains to promote my website (the 10 clips on my homepage) and when I imported the footage the import gave me the same audio issue. I was able to get out most of the noise but it seems like it shouldn't be an issue.

My previous camera wasa canon GL-1 and i still use it when Im just going out to do a fun little thing-a-ma-jig type shoot and I never have any sound issues.

What do you think it could be?
 
Could possibly be your audio gear- might want to monitor direct through headphones. And of course check your sample rates in the camera and in your sequence settings.

Noah
 
When I monitor my audio, I don't hear any noise. It's clear. It's only after the import. Whatshould my sample rates be set to in my sequence settings?
 
48k 16bit...

How are you monitoring from the system? Thru FW to a deck and out or just out via the mac's monitoring abilities?

See if you can switch it around to the other.

Same thing?

CaptM
 
Everything should be 48Khz/16-bit. Also make sure your realtime audio playback quality is set to high. This is in your User Preferences under the General Tab.

-Noah
 
Dudes... this is likely just ANALOG electrical noise generated by your computer. My computer makes all kinds of low sporadic hums, beeps, chatters, and chirps that come through on the analog outputs but not on the digital outs or through audio hardware. If you can, try dedicated audio interface, or use the TOSLINK out on your mac to get a non-contaminated signal.

Computers are extremely electrically noisy, and a terrible place for any analog audio processing to take place - that's why good audio hardware has all the A/D/A in outboard boxes.

PS... didn't think of it before... try monitoring through your camera via firewire
 
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I switched my audio from the speakers to the toslink port but now I'm not getting any sound. What do I need to do to fix this?
 
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I uploaded it a clip from a tiny little itty bitty short that I'm doing on myspace so you can all hear the sounds/ hums/ chirps and burps. I don't hear them on playback only after I import. Any suggestions on hardware that I would need to purchase would be extremely helpful. New sound card?? audio interface?? I just need the static to go away.

I feel like Jim Carrey in "23" I actually never saw the film but remember in the trailer he was obsessed with the number 23. I feel exactly how he felt, but with this terrible static!!! heheheh

http://www.mattadamsapple.com/dvxuser/help.mov
 
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Hmmm.... I listened to your clip, and I don't hear the type of noise I was talking about. Of course, I wouldn't hear it, if the noise is coming from your computer... the noise I described is not in the data, it's in the electrical environment of your computer, so no uploaded video would have it unless you re-recorded your computer's analog output...

At first it sounded like a problem with audio levels, but looking at the waveforms it doesn't seem like that - it seems almost to be a frequency-dependent resonance somewhere. Are you absolutely sure it's not present when playing back from the camera? Also, your video had a mono audio track... how is that generated? Are you panning two tracks to the center? Make sure to check the individual tracks to make sure it's not a blending problem...
 
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I don't see how the audio could change so fast to create such dramatic digital noise. Don't you think it has to have something to do with my signal on import or like you said boosted levels on import.

When I put on my headphones with no music I hear snaps and crackes and pops ALL the time.

When I play the video from my camera to my televsion at the same level as my computer speakers there is no problem.

The problem only occurrs when I import the audio into an editing suite. I've had the same result with Avid and FCP.

I'm going to try to capture the footage on another system and see what happens and I will keep you posted. Thanks for all your help!
 
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Well, you can't really compare unless you're listening to both through the same speakers... have you tried playing the audio via the camera through firewire, with the camera hooked up to exactly the same playback system? Headphones definitely emphasize a lot of noise, especially snaps and crackles!

Are you saying ("headphones with no music") that you hear the noise even when you're not playing any sound on the computer? Then that does point towards analog noise generated by the computer.

TOSLINK is an optical digital connection that uses a special optical cable. If you're computer has an optical out, and you have, say, a home-theater system with an optical in, then you can avoid the computer's electrical contamination...
 
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