Removing clicks

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hogiewan
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I recorded my father-in-law this past Saturday. He's got a great guitar and great technique, so I knew it would come out good, but he also induces noise. He had his aortic (heart) valve replaced a couple years ago and now has a plastic valve - that clicks. That's right, his chest clicks.

I decided to record the guitar with 2 mics (AKG 451 and 414) in a mid-side setup. I pointed the mics at the 12th fret from slightly above the guitar to try to get his chest to the null side of the setup (side mic already had the null facing him, but I was trying to get the click to the side of the cardioid).

Alas, there is still some clicking on the track:

sample

What's the best way to minimize the clicks?

duffrecords
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Judging by the sample, you won't be able to completely remove those clicks but you might be able to hide them a little more. Try Audacity's Click Removal or Noise Removal features in the Effects menu. Unfortunately, once noise like that gets into a recording it's near impossible to eliminate without compromising the sound quality (and those are such sweet-sounding mics). Perhaps a neoprene wetsuit would help on future recordings.

thorgal
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maybe you should re-record him with a thick pillow between the chest and the guitar ??

hogiewan
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I thought about putting something on his chest, but I'd rather him be comfortable and get a good performance with clicks, than get an ok performance without them. Also, I didn't tell him I was worried about picking up the clicking until after we were done. He tends to get nervous or self-conscious about that sort of stuff, and I didn't want his heart beating any faster/harder, making more prominent clicking.

duff - I know I won't be able to remove them. I should have titled the thread "Reducing clicks". Audacity's click removal didn't touch them, and the noise removal always makes the audio sound weird. I tried playing with a notch filter to kill the main frequency of the click, but I just could find it.

thorgal
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it's a very tough one to change afterward. These clicks (I heard your sample) are not just a few frame wide ... if it had been so, you could have removed these frames and dithered / extrapolated from neighboring frames. Just this editing process is way too boring to do manually ... maybe you could find a compromise and make him play something that goes along the rythm of the clicks (no joke here, I really sympathize with you) ?

duffrecords
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That's true... I thought about mentioning that extrapolation technique but it is extremely tedious. If you have the patience (and are willing to use proprietary software) you could use the repair function in Sound Forge. You'd have to traverse the entire file and mute each click, then repair each gap. I apologize for suggesting non-free software on this forum. Please correct me if such a function exists in Ardour or Audacity.

Dark Horse
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Have you tried the Gnome Wave Cleaner?
here is the link to the Wiki page
http://en.wikipedia.org/wiki/Gnome_Wave_Cleaner
I hope it helps.
Mark

DrG
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Get him to play a semi-acoutsic and DI it.. ;)

hogiewan
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He was just in town for the day, and it needs to be done before I leave town this Saturday. I recorded the pickup in his guitar at the same time as the mics. By blending the two sources, the clicks are low enough. They are slightly noticeable at the beginning of the song, but most people I've played it to couldn't hear the clicks even when I pointed them out.

I have a shaker that comes in at the middle of the first verse that plays throughout which masks the clicking. Also, I've done some eq/notch filtering that minimizes it

Next time I record him, we'll have to fashion something to reduce the sound from his valve.

I'll post the final version when I'm done.

hogiewan
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I recorded the m/s mics as a stereo track (to use the MS to Stereo matrix plugin). The click is almost exclusively in the mid mic (left). How do I isolate just the left half?

My first thought was an insert sending the left side to a mono bus. leaving the right alone, but that kills the signal path for the right. So I guess I could just make a bus for the right side and let the signal pass right through.

Is there a better way?

thorgal
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... maybe you can split the stereo track into mono-regions if you want more flexibility. There's a function in the region context menu which allows you to do that. In the region tab, you will see two new regions that you can eventually import into mono tracks.