How to remove this noise

[Bolly]

These recordings were made with a stock Pana MX8/DV852 cam over the
past year. Over this period I have really started to get annoyed by
this noise some
say is generated by the UN-overridable autogain whenever the input
level changes rapidly. Will be taking the unit back over the w/e but
still left
with 4 hours of home videos ruined.
I have managed to attach spectral images of the waveforms (cooledit),
showing the noise very nicely, only don't know how to remove them...
Any input would be much appreciated.
three small samples and the spectral images at:
http://homepage.ntlworld.com/bet.trojak/sounds/

Many thanks: Bolly

[Scott Dorsey]

Bolly > wrote:
>These recordings were made with a stock Pana MX8/DV852 cam over the
>past year. Over this period I have really started to get annoyed by
>this noise some
>say is generated by the UN-overridable autogain whenever the input
>level changes rapidly. Will be taking the unit back over the w/e but
>still left
>with 4 hours of home videos ruined.

The noise isn't caused by the automatic gain control. The annoying
pumping is caused by the automatic gain control. The noise is caused
by poor mike technique, probably using the on-camera mike.

>I have managed to attach spectral images of the waveforms (cooledit),
>showing the noise very nicely, only don't know how to remove them...

Sorry, you're going to have to loop the dialogue over. Or just dump
the dialogue completely and lay in a nice music track.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Bolly]

Robert Gault > wrote in message >...

> The short wave files are not very good for determining what you hear as
> noise. That's because there is so much going on and the clips are so
> short that we can't tell what should or should not be present.
>
> Looking at the .jpg files shows a common pattern that ought to be what
> is bothering you but may not be. These are the full height rectangles
> which indicate something unusual and monophonic in nature.CoolEdit
> could easily remove these and if you can overwrite your audio track with
> CoolEdit processed files, this specific noise pattern can be removed.
Yes these are the ones, the full height rectangles.
I cannot figure out how to remove them in cooledit, without loosing
the rest of the high end...


> Your real question should be what is causing the noise, whatever the
> noise actually is. That is going to require a different approach aimed
> at identifying the noise. Make a recording under the same conditions as
> these were but with no people present. See what if anything can be heard
> as an ambient noise background.
It only happens, when there is a rapid change in "loudness". When I
am recording a distant event in a relative quiet environment, it
doesn't happen.


> If there is noise in the camera, then it will be present and visible
> with CoolEdit. If the noise is being cause during volume changes, turn
> on a radio to inter station hiss and periodically turn it up loud so
> that the camera gain controls activate. Again, if something shows up,
> CoolEdit should see it.
Yes I am sure its the camera, and will be returning it under warranty.
I'd like to repair the existing recordings though.

> The point of this experiment is that you will have controlled conditions
> and know exactly what sound should be present. Anything unexpected is
> being caused by the camera. Your "home videos" have too much going on to
> be useful for troubleshooting.