Thread: Help needed erasing a 'rumble' from a interview track.

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  1. #1 Help needed erasing a 'rumble' from a interview track. 
    Hello!

    I'm no stranger here in asking for help. I've had an very unfortunate issue with onboard camera audio recently. My electronic FF developed a 'jitter' during an important interview I captured off-the-cuff and is audible.

    I've uploaded it here: https://youtu.be/zjjeT18cDUs

    You will hear the FF as a 'rumble' sound throughout the whole audio track.

    I'm in a terrible predicament here and I'm tearing my hair out. If there are any audio pros out there able to advise me I'd really, really appreciate it. Even if it cleans up 10% of the issues it's honestly worth it to me.

    Many thanks

    Alex
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  2. #2  
    Senior Member Karim D. Ghantous's Avatar
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    Oh damn. What a fucking bastard of a problem. I suppose you could use some advanced audio software to separate the layers of frequency, and try to eliminate the one in question. You could try Audacity to start with - it might have a filter to remove wind noise, which might work in this case. I am ignorant of audio issues but I hope that I've given you some ideas.

    Thankfully, audio processing is two orders of magnitude simpler than video. I know that you can easily remove vocals from audio clips in Audacity. Let's hope that this issue is not much more complicated.

    I hope that you have sent an email to the manufacturer of the FF and explained the problem.

    EDIT: I've had a play with Audacity, and I noticed that the low pass filter partially isolated the clicking noise. Perhaps you can use this track to somehow subtract from the original track? I'll keep playing.

    EDIT 2: Here is another idea. The clicking sound might affect both L & R channels the same, while the vocals will be slightly different between channels. Maybe this data can somehow preserve channel differences while eliminating similarities?
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  3. #3  
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    https://www.izotope.com/en/products/...d-edit/rx.html

    You would likely want to get the more expensive version but it gives you more tools.
    You can literally “paint” sound frequencies out of your track.
    Try the demo and see if it works.

    While I have doubts you can eliminate the rumble
    I’m pretty confident you can bring the rumble down to a more acceptable level.
    BTW- I’m not an “audio guy” but I have had to manage similar predicaments.

    Brian Timmons
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    I can only speak for an older software by Syntrillium Software called Cool Edit Pro v1.5. It was bought out by Adobe and renamed Adobe Audition. If you are editing on Adobe and have Audition, there will be a 30 channel graphic equaliser in there which is pretty good at lowering narrow frequency bands. The unwanted noise seems to lie within a fairly narrow frequency. The voice recording is crisp and strong and its main elements seem to land outside of the band you would want to suppress.

    My first effort would be to play with the graphic equaliser. Your unwanted sound seems to be around 600Hz and maybe some harmonics of that. I think you have a preview mode where you can try it non-destructively. That much may make the recording acceptable without too much extra work.

    My second effort would be to try to find a spot in the recording where there is no voice or decaying room reverb where there is only the unwanted sound. I would take a noise sample from that and then attempt noise reduction based on that sample.

    My third effort would be if there is a two-channel or stereo recording, to experiment with the channels and delays across the channels. I have forgotten what that function is called. Sometimes you can achieve an "apparent" reduction of an unwanted sound by some cross mixing of one channel into the other even with a mono recording when this is copied to make a stereo pair. It will introduce a new airiness or slight reverb which may not be desirable in your instance.

    Please take greater heed of others more qualified in this game than I. It has been a few years since I used Cool Edit Pro for recoveries from old scratchy 78rpm records.
    Last edited by Robert Hart; 08-11-2018 at 11:23 PM. Reason: error
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  5. #5  
    Senior Member Karim D. Ghantous's Avatar
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    Quote Originally Posted by Robert Hart View Post
    My first effort would be to play with the graphic equaliser. Your unwanted sound seems to be around 600Hz and maybe some harmonics of that. I think you have a preview mode where you can try it non-destructively. That much may make the recording acceptable without too much extra work.

    My second effort would be to try to find a spot in the recording where there is no voice or decaying room reverb where there is only the unwanted sound. I would take a noise sample from that and then attempt noise reduction based on that sample.
    FWIW I tried the first method in Audacity but it doesn't work.

    I tried the second, and although it helped, it wasn't 100%, although I didn't play around with the variables. I'm not surprised that it didn't work 100%, as the noise is not consistent, such as a hiss would be. Either way, it should have been the first thing I thought of, as it's one of the few things that pretty much every podcaster/vlogger knows about (though I'm not in either camp).

    What I did: select a section of audio with no voice, but with the unwanted noise. I then went to Noise Reduction..., and clicked on Get Noise Profile. I then selected the entire track, and went back to Noise Reduction... and clicked OK. Then I went to Compressor and applied it. I hope that this can be of some value.

    To make this technique work better: identify places in the recording where the noise is different, and take multiple NR samples and apply it to the relevant section of audio. You could also try to apply it more strongly to gaps in the dialogue. It's not impossible but you might want to hire someone to do this properly. Good luck!

    Edit: If you want screenshots, let me know, although Audacity is very easy to use.

    Edit 2: If you are stuck, go to a site like Fiverr and find someone who can do that operation for a few dollars. Even $25 would be very cheap IMO. I'd happily give it a try at no cost to you, but audio is not my domain, and I think you will get a much better result from someone who understands audio properly. Spend the $25. ;-)
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  6. #6  
    Quote Originally Posted by Karim D. Ghantous View Post
    Thankfully, audio processing is two orders of magnitude simpler than video.
    That is completely wrong. Depending on what you do it can be more complex than video.

    In many cases orders of magnitude more complex.


    Quote Originally Posted by Karim D. Ghantous View Post
    I know that you can easily remove vocals from audio clips in Audacity. Let's hope that this issue is not much more complicated.
    The issue is much more complicated than that.

    Noise is masking the voice and removing one damages the other.

    Quote Originally Posted by Karim D. Ghantous View Post
    EDIT: I've had a play with Audacity, and I noticed that the low pass filter partially isolated the clicking noise. Perhaps you can use this track to somehow subtract from the original track?

    No.
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  7. #7  
    Quote Originally Posted by Alexander Tabrizi View Post
    I've had an very unfortunate issue with onboard camera audio recently.
    It only seems that way. In reality you made a bunch of mistakes. First was not hiring a sound guy, second attempting to record an interview audio with an on-camera mic, third not using headphones to monitor what you shoot. Had at least one of those been avoided, there would not be an "unfortunate issue".

    Quote Originally Posted by Alexander Tabrizi View Post
    If there are any audio pros out there able to advise me I'd really, really appreciate it.
    Audio pros in post would tear their hair out on this audio more than you are currently, with additional facepalm and/or head banging on the console while sound recordists would seek either pills or hard drink to calm down and once the initial emotion settles down in general would advise you not to make a fourth mistake by wanting to wiggle out of this and attempt the DIY fix without knowledge to do it properly, but bite the bullet and hire someone skilled to do it.

    While that won't lead to a proper sound, will damage the vocals and cost you, it will a) get vastly superior result than what you can do by yourself (more than 10% better ) b) teach you a valuable lesson and c) not propagate relying on making mistakes such as these which undervalue the craft of sound recording and post production.
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  8. #8  
    Senior Member Blair Thornton's Avatar
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    Quote Originally Posted by Brian Timmons View Post
    https://www.izotope.com/en/products/...d-edit/rx.html

    You would likely want to get the more expensive version but it gives you more tools.
    You can literally “paint” sound frequencies out of your track.
    Try the demo and see if it works.

    While I have doubts you can eliminate the rumble
    I’m pretty confident you can bring the rumble down to a more accept level.
    BTW- I’m not an “audio guy” but I have had to manage similar predicaments.

    Brian Timmons
    BRITIM/MEDIA
    I agree, iZotope is the best tool to fix this clip. With that said, it's a very difficult clip to fix.

    I gave a shot at fixing it with iZotope https://www.dropbox.com/s/78e56txwca...%2001.wav?dl=0
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  9. #9  
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    Quote Originally Posted by Karim D. Ghantous View Post
    Thankfully, audio processing is two orders of magnitude simpler than video. I know that you can easily remove vocals from audio clips in Audacity. Let's hope that this issue is not much more complicated.
    You must have a bizarrely different idea of what "easily" means than I do?

    Quote Originally Posted by Hrvoje Simic View Post
    It only seems that way. In reality you made a bunch of mistakes. First was not hiring a sound guy, second attempting to record an interview audio with an on-camera mic, third not using headphones to monitor what you shoot. Had at least one of those been avoided, there would not be an "unfortunate issue".



    Audio pros in post would tear their hair out on this audio more than you are currently, with additional facepalm and/or head banging on the console while sound recordists would seek either pills or hard drink to calm down and once the initial emotion settles down in general would advise you not to make a fourth mistake by wanting to wiggle out of this and attempt the DIY fix without knowledge to do it properly, but bite the bullet and hire someone skilled to do it.

    While that won't lead to a proper sound, will damage the vocals and cost you, it will a) get vastly superior result than what you can do by yourself (more than 10% better ) b) teach you a valuable lesson and c) not propagate relying on making mistakes such as these which undervalue the craft of sound recording and post production.


    I agree. And potentially the OP should just bite the bullet and pay for a reshoot, this time with a sound recordist!
    http://IronFilm.co.nz/Sound/ (Sound Recordist based in Auckland, NZ. Happy to travel too)
    https://www.youtube.com/c/SoundSpeeding
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