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I have been recording lectures, but unfortunately these contain a lot of chalk sounds. Is there any way of removing these?


  • List item - Removing noise from a recording - this seems to be removing background noise ect which I don't think covers chalk sounds
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Any chance of getting a sample to play with? We might be able to give you a more accurate solution... – John Barrett Sep 23 '09 at 13:53
Thanks for the offer, but I've decided to just tolerate the sounds until the end of semester and try to play with all these stuff during the holidays – Casebash Sep 24 '09 at 0:09
up vote 9 down vote accepted

Programs like Audacity let you create a "noise profile" which is then used to remove noise on the recording. If you can find a few seconds where the only sound is the chalk-board noise, then you can try that.

IME, noise reduction works better in multiple passes than trying to catch it all in one pass.

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I know it won't help what you've already recorded, but I think the real solution here is to think about where and how you position and configure the mic.

That said, +1 for Audacity to clean up the existing recordings.

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The most annoying part of the chalk is probably the higher frequencies (squeaking), so a simple EQ pass might be able to make the recording more tolerable. Audacity has a few plugins that do EQ. A bit of trial and error and you should be able to quiet the highest frequencies while leaving the voice audible.

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You could always use a sound-editing program like Audacity (free, open source) and clip them out.

I'm not sure what to do if the chalk noises happened while the instructor was talking, though.

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