cliped sound!

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stoo
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Joined: May 28 2001

Ok hears the problem…
At home I have prem 6.5. I use a canon xm2 and a xl1s. I have a sony gdv300 mini dv deck which I use to capture my footage. I’m using a storm 2 capture card and the sound card is a sound blaster audigy.
When I capture and edit my footage it sounds fine.
At uni I have to use adobe audition. If I take video clips in and then import a video clip when I analyse the sound it tells me its clipped. I’ve been told to make a wav file up of the audio from the video clip an edit that… as in don’t import the video into audition.. this how ever is still clipped according to audition. It sounds fine to me and it doesn’t sound clipped. After finding this problem I hooked a Panasonic svhs hs 800 deck to my sony dv deck. The sound levels on the svhs deck go in to the red which would indicate its clipped however it doesn’t sound clipped?…after finding this out I imported the clip in to after effects 6 and found that according to the sound levels it was clipped to.elimate the clipping I had to reduce the sound by –3db
What Id like to no and I no this may seem stupid but is the sound clipped? If it is why carnt I hear it? and how can I get rid of the this problem?.

colin rowe
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Joined: Dec 16 2000

Try finding the clipped areas on the wav and use the clip restoration tool on those segments. Audio should clip occasionaly. When you set up a mic you should watch the audio level meter, if it does not peak at least occasionally (at high input levels) you should increase the gain, if it peaks frequently or continuously you should turn the level down. You say the sound levels seem ok to your ear, if that is the case I wouldnt bother adjusting it. If you have continuous clipping you would be very aware of its presence. Occasional clipping is normal.

Colin Rowe

stoo
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Joined: May 28 2001

Thanks for the reply
As for the sound it’s only something I’ve noticed since using audition. And when I say noticed I carnt actually hear the clipped parts, every one I’ve asked also carnt hear the clipped parts. We have listed to the sound on earphones and speakers ranging from crap quality to very good quality
During the week I filmed some inter views on my xl1s using a k6 with tie clip mic. The sound is excellent and I’ve just checked the sound in audition and it seems fine. No clips
It seems that the problem tape I noticed it on was recorded on a sony vx1000 and then copied to an xm2. the sony used 12 bit 32Khz sound where as the xm2 uses 16bit 48Khz sound. Could this be where the problem is? I’m going to try out the sound on the xm2 to see if this has the problem.
chop

harlequin
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Joined: Aug 16 2000

i never set my cameras to 12bit 32khz , i have no need of a second soundtrack on the tape.

i prefer sticking to 16bit 48khz and adding any other sounds in the editing software.

if i get given any non 16bit 48khz sounds i re-encode to 16bit 48khz before i start editing.

it may not be the best way to do it , but i don't have many problems doing it this way.

Gary MacKenzie

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John Willett at Home
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Joined: Jun 29 2001
Quote:
Originally posted by colin rowe:
... Audio should clip occasionaly...

NO audio should never clip !

If you are recording analoguse it is safe and normal to let the red light show occasionally - but that is not clipping.

Clipping is in digital recording and you exceed FSD (Full Scale Digits) and the waveform is just chopped off.

This should never be allowed to happen and the recording level reduced to prevent it.

John

stoo
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Joined: May 28 2001

Ok thanks again for the response.
with the vx1000 cam it recorded sound at 12 bit 32Khz. I thort this was because it was one of the first dv units?. So I had no choice and I wasn’t recording a second sound track. I to always record at 16bit 48Khz. I used to own a vx1000 and the tape which I noticed the clipping on was copied from the vx1000 to an xm2.
Getting back to the clipping I’m going on the results that audition gives when I analyse the wav file. I couldn’t hear any clipped audio, but when I ran the same audio throw after effects it also indicates that the audio is clipped?. If I cant hear its clipped and no one else can dose it mean it is clipped? Or dose the software assume its clipped because its close to the clipping value?

thanks agin for the posts

busbyvideo
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Joined: Feb 7 2002

Clipping: The type of distortion caused by gross overload. The resulting loud, harsh and unpleasant sound may cause damage to a hi-fi system, particularly loudspeaker drive units. Clipping is so named because of its reference
to the sharp truncation of the AC signal waveform.

http://www.enjoythemusic.com/magazine/definitions/audioterminology.htm

If you don't hear the above distortion then i woud'nt worry about it.

Mike

colin rowe
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Joined: Dec 16 2000

Original post by John Willett at home
NO audio should never clip
If you are recording analoguse it is safe and normal to let the red light show occasionally - but that is not clipping.

Exactly what I meant John. You put it so much clearer
Colin

Colin Rowe