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#1
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Best way to remove mic feedback in post?
I recorded a live show where there are several instances of mic feedbacks. I
want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. Most audio editors have notch filters, but to complicate things, the mic feedback changes frequency slightly as it gets louder. Is there a filter that automatically adjust to the frequency change and remove the feedback? |
#2
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Best way to remove mic feedback in post?
On Sun, 13 Oct 2013 10:04:59 -0700, "bob" wrote:
I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. Most audio editors have notch filters, but to complicate things, the mic feedback changes frequency slightly as it gets louder. Is there a filter that automatically adjust to the frequency change and remove the feedback? Use Adobe Audition in spectrum view. You can draw around the squeal with the lasso tool and delete it. Works seriously well. Filters are too coarse and clumsy for this job. d |
#3
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Best way to remove mic feedback in post?
bob wrote:
I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. Most audio editors have notch filters, but to complicate things, the mic feedback changes frequency slightly as it gets louder. Is there a filter that automatically adjust to the frequency change and remove the feedback? Probably not, this needs an operator. At a glance - using A3 - I would cut up in segments and use FFT analysis and FFT eq. It may be possible to define a few categories. It is possible to define very narrow filters, example for 50 Hz hum: 45 Hz 0 dB, 46 Hz 0 dB, 47 Hz 0 dB 48 Hz 0 dB, 49 Hz -36 dB, 50 Hz -36 dB, 51 Hz -36 dB, 52 Hz 0 dB, 53 Hz 0 dB, 54 Hz 0 dB, 55 Hz 0 dB. The objective of the extra points is to tell the algorith that you want a sharp corner. The FFT equalizer is well suited for removing what you do not want because it is phase linear. It is less well suited to compensate for minimum phase deviations such as those caused by transducers. This is not a problem to solve with the notch filter function. You must use 32 bit audio for optimum sound quality, especially as it may end up being a multistage process. It may be that you end up with the filters sharp enough, but have to do the filtering twice. Use splines, use dB display. Note: the software is broken by design, so you MUST define filters in the actually used samplerate, I do not know whether they fixed it in the new version. It reportedly doesn't have open append, which I use a lot, so I skipped it. If you divide this in three piles of numbered segments it may get batchable. Use - ta da - open append to reassemble the audio, multiselect works, but select from last to first. There is also frequency display editing in A3, it effectively does about the same and is perhaps better suited for the actual problem, but you have better control over the process by the above suggested method. Kind regards Peter Larsen |
#4
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Best way to remove mic feedback in post?
Don Pearce wrote:
On Sun, 13 Oct 2013 10:04:59 -0700, "bob" wrote: I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. Most audio editors have notch filters, but to complicate things, the mic feedback changes frequency slightly as it gets louder. Is there a filter that automatically adjust to the frequency change and remove the feedback? Use Adobe Audition in spectrum view. You can draw around the squeal with the lasso tool and delete it. Works seriously well. Filters are too coarse and clumsy for this job. Or Sony SpectralLayers, or equivalent in Wavelab. geoff |
#5
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Best way to remove mic feedback in post?
In article , bob wrote:
I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. Most audio editors have notch filters, but to complicate things, the mic feedback changes frequency slightly as it gets louder. Is there a filter that automatically adjust to the frequency change and remove the feedback? No, there isn't. But I bet a nickel that the frequency change is psychoacoustic and isn't an actual physical change. Look at a spectral plot! Years ago I would have recommended manual use of notch filters, but these days there are a variety of retouching tools that will let you look at a frequency/time/amplitude plot and rework it. CEDAR made the original one but Izotope has one as well now. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#6
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Best way to remove mic feedback in post?
On 10/13/2013 1:04 PM, bob wrote:
I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. The tool for this job is a relatively new one (actually an old concept with a new user interface) which in essence filters a defined frequency range for a specific time period. It's usually called "spectral equalization" and Adobe Auditon has a version of it. You view the audio with a spectrogram display that uses color to indicate amplitude and displays frequency as height along the vertical axis. The horizontal axis is time. Feedback is pretty easy to see on this dispay if you look sharp while the audio is playing. You "lasso" the (usually bright red) blob using the mouse and press the "cut" button. It takes a little finesse to take enough but not too much, but with patience you should be able to clean up the recording pretty well. Note that I said "with patience." This isn't an automatic process by any means. You have to find the feedback and trim it out unobtrusively, but these tools are capable of doing so much more and better than before we had it available. -- For a good time, call http://mikeriversaudio.wordpress.com |
#7
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Best way to remove mic feedback in post?
On Mon, 14 Oct 2013 17:54:30 -0400 "Mike Rivers" wrote
in article On 10/13/2013 1:04 PM, bob wrote: I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. The tool for this job is a relatively new one (actually an old concept with a new user interface) which in essence filters a defined frequency range for a specific time period. It's usually called "spectral equalization" and Adobe Auditon has a version of it. You view the audio with a spectrogram display that uses color to indicate amplitude and displays frequency as height along the vertical axis. The horizontal axis is time. Feedback is pretty easy to see on this dispay if you look sharp while the audio is playing. You "lasso" the (usually bright red) blob using the mouse and press the "cut" button. It takes a little finesse to take enough but not too much, but with patience you should be able to clean up the recording pretty well. Note that I said "with patience." This isn't an automatic process by any means. You have to find the feedback and trim it out unobtrusively, but these tools are capable of doing so much more and better than before we had it available. FWIW, you can increase the resolution of the spectrogram display by right-clicking. There are 3 steps beyond the default. I guess this reflects the fact that generating the display takes a fair amount of computation. Right-clicking also allows selection of the range of frequencies that is displayed - this came in handy when I was trying to get rid of an ambulance siren in a live recording last year. |
#8
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Best way to remove mic feedback in post?
On Sun, 13 Oct 2013 10:04:59 -0700, bob wrote
(in article ): Is there a filter that automatically adjust to the frequency change and remove the feedback? ------------------------------snip------------------------------ Not quite automatically, but you can get some pretty good results with the new iZotope RX3 standalone: http://www.izotope.com/products/audio/rx/index.asp?hs13 Find the worst instances of feedback, let iZotope analyze it, and then you can have it build some notch filters to knock it out as much as possible. My experience is that you can generally remove at least 50% of problems like this, then solve the rest just through careful level adjustment and EQ. It's never perfect, but it'll be an improvement. --MFW |
#9
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Best way to remove mic feedback in post?
On Mon, 14 Oct 2013 17:54:30 -0400, Mike Rivers wrote:
On 10/13/2013 1:04 PM, bob wrote: I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. The tool for this job is a relatively new one (actually an old concept with a new user interface) which in essence filters a defined frequency range for a specific time period. It's usually called "spectral equalization" and Adobe Auditon has a version of it. You view the audio with a spectrogram display that uses color to indicate amplitude and displays frequency as height along the vertical axis. The horizontal axis is time. Feedback is pretty easy to see on this dispay if you look sharp while the audio is playing. You "lasso" the (usually bright red) blob using the mouse and press the "cut" button. It takes a little finesse to take enough but not too much, but with patience you should be able to clean up the recording pretty well. Note that I said "with patience." This isn't an automatic process by any means. You have to find the feedback and trim it out unobtrusively, but these tools are capable of doing so much more and better than before we had it available. another Plus-1 for spectral editing. The Spectral display and editing feature in Audition makes cleaning up narration tracks easy compared with wave-form editing. It is at least as big a jump in capability as moving from analogue tape and razor blade to digital wave form editing. Various mouth noises as well as extraneous noises like clothing rustles, stop watch clicks, and script handling noise are easily removed... all not really achievable or practical in waveform editing. Steve King |
#10
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Best way to remove mic feedback in post?
another Plus-1 for spectral editing. The Spectral display and editing feature in Audition makes cleaning up narration tracks easy compared with wave-form editing. It is at least as big a jump in capability as moving from analogue tape and razor blade to digital wave form editing. Various mouth noises as well as extraneous noises like clothing rustles, stop watch clicks, and script handling noise are easily removed... all not really achievable or practical in waveform editing. On the contrary I still find it better/easier to reduce plosives in waveform edit, or fixed notch filter/s for any mains hum. Watch clicks or any other short sharp spikes are probably easier done in waveform edit too IMO. Spectral editing certainly works better for some things however. Trevor. |
#11
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Best way to remove mic feedback in post?
On Wed, 16 Oct 2013 16:29:00 +1100, Trevor wrote:
another Plus-1 for spectral editing. The Spectral display and editing feature in Audition makes cleaning up narration tracks easy compared with wave-form editing. It is at least as big a jump in capability as moving from analogue tape and razor blade to digital wave form editing. Various mouth noises as well as extraneous noises like clothing rustles, stop watch clicks, and script handling noise are easily removed... all not really achievable or practical in waveform editing. On the contrary I still find it better/easier to reduce plosives in waveform edit, or fixed notch filter/s for any mains hum. Watch clicks or any other short sharp spikes are probably easier done in waveform edit too IMO. Spectral editing certainly works better for some things however. Trevor. I go back and forth depending on what works best for the problem. However, I do find that certain clicks and mouth noises are much easier to locate in spectral view--don't have to expand the wave form four or five clicks to find the little nigglies. Hum and pervasive junk is definitely better dealt with using notch filters or, for complex noise, the restoration noise reduction tool. Then, there is the issue of maintaining lip sync, where the spectral view and the lasso can remove the problem without affecting shortening the audio track. Steve King |
#12
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Best way to remove mic feedback in post?
another Plus-1 for spectral editing. On 10/16/2013 1:29 AM, Trevor wrote: On the contrary I still find it better/easier to reduce plosives in waveform edit, or fixed notch filter/s for any mains hum. Watch clicks or any other short sharp spikes are probably easier done in waveform edit too IMO. The better you can see what you want to remove, the better use you can make of a spectral editor. That's the key to using that tool. One nice feature of Spectral Layers is that if you identify the hum, you can tell it to also process harmonics. This works better than multiple notches with line buzz that always contains harmonics. -- For a good time, call http://mikeriversaudio.wordpress.com |
#13
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Best way to remove mic feedback in post?
"Mike Rivers" wrote in message ... On the contrary I still find it better/easier to reduce plosives in waveform edit, or fixed notch filter/s for any mains hum. Watch clicks or any other short sharp spikes are probably easier done in waveform edit too IMO. The better you can see what you want to remove, the better use you can make of a spectral editor. True. That's the key to using that tool. One nice feature of Spectral Layers is that if you identify the hum, you can tell it to also process harmonics. This works better than multiple notches with line buzz that always contains harmonics. Yep they usually do, but I can fine tune each notch better with a good notch filter IME. YMMV depending on the actual tools. Nice to have options in any case. Trevor. |
#14
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Best way to remove mic feedback in post?
On 10/22/2013 4:19 AM, Trevor wrote:
One nice feature of Spectral Layers is that if you identify the hum, you can tell it to also process harmonics. This works better than multiple notches with line buzz that always contains harmonics. Yep they usually do, but I can fine tune each notch better with a good notch filter IME. I bet you really can't, but Spectral Layers is complicated enough to use so that if you have a way that works for you, you should stick with it. And, really, there should be no reason to fine-tune each notch. Find the right one (usually or 120.0 Hz will be close enough) and then just use arithmetic to set the others. In Spectral Layers you can set the level below which the "harmonic finder" will select harmonics, so if 480 Hz is below -95 dBFS, it won't include it in the buzz "layer." -- For a good time, call http://mikeriversaudio.wordpress.com |
#15
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Best way to remove mic feedback in post?
"bob" wrote in message ... I recorded a live show where there are several instances of mic feedbacks. I want to salvage as much as possible from those instances. I have several audio/wave editors (adobe audition, soundbooth, audacity, goldwave) at my disposal. The Very Narrow DTMF filter in Audition is my fave. Just plug in the frequency of the feedback (obtain from spectral analysis with 65k points) and go. Most audio editors have notch filters, but to complicate things, the mic feedback changes frequency slightly as it gets louder. Do it in segments Is there a filter that automatically adjust to the frequency change and remove the feedback? Never heard of it. |
#16
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Best way to remove mic feedback in post?
"Mike Rivers" wrote in message ... On 10/22/2013 4:19 AM, Trevor wrote: One nice feature of Spectral Layers is that if you identify the hum, you can tell it to also process harmonics. This works better than multiple notches with line buzz that always contains harmonics. Yep they usually do, but I can fine tune each notch better with a good notch filter IME. I bet you really can't, but Spectral Layers is complicated enough to use so that if you have a way that works for you, you should stick with it. And, really, there should be no reason to fine-tune each notch. Find the right one (usually or 120.0 Hz will be close enough) and then just use arithmetic to set the others. Determining frequency is the easy part with any spectrum analyser, I still want to fine tune notch width and depth. In Spectral Layers you can set the level below which the "harmonic finder" will select harmonics, so if 480 Hz is below -95 dBFS, it won't include it in the buzz "layer." True, I obviously need more experience with Spectral Layers, but the spectragram display already in SoundForge has allowed me to easily accertain that for a decade or so. (and 3rd party tools before that) But as I said, I'm all for options and new tools! One may work better for me on one job, and the opposite for another. Trevor. |
#17
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Best way to remove mic feedback in post?
In article , Trevor wrote:
"Mike Rivers" wrote in message ... On 10/22/2013 4:19 AM, Trevor wrote: One nice feature of Spectral Layers is that if you identify the hum, you can tell it to also process harmonics. This works better than multiple notches with line buzz that always contains harmonics. Yep they usually do, but I can fine tune each notch better with a good notch filter IME. I bet you really can't, but Spectral Layers is complicated enough to use so that if you have a way that works for you, you should stick with it. And, really, there should be no reason to fine-tune each notch. Find the right one (usually or 120.0 Hz will be close enough) and then just use arithmetic to set the others. Determining frequency is the easy part with any spectrum analyser, I still want to fine tune notch width and depth. In the case of buzz, you want the deepest and most narrow filter you can get away with. In the analogue world there was a lot of worrying about how tight you could get because the buzz frequency would drift slightly with tape speed and there was worrying about how deep you could get because the filter had audible side effects. But in the digital world where everything is rock-steady, the majority of the fine tuning is deciding just how many of the individual harmonics of the buzz you want to knock out. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
#18
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Best way to remove mic feedback in post?
I don't know if you have access to Izotop RX, but you should be able to get rid of that in stand-alone mode using "spectral repair". I hope this helps.
Ken / Blueberry Buddha (aka Eleven Shadows) www.blueberrybuddha.com (first time I've posted here in eons!) |
#19
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Best way to remove mic feedback in post?
Apologies, for some reason, I didn't see all the other replies at first, so I see this has been addressed quite well already.
Ken / Blueberry Buddha |
#20
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Best way to remove mic feedback in post?
Adobe Audition spectral editor all the way so easy just like lifting a layer off in Photoshop.
Takes just a few min to get the hang of it but the easiest quickest way to get rid of any feedback and no affect the underlying track. By the time you use an FFT analysis and FFT EQ cut things up and batch em back i will have cleaned the whole track and have moved on. Too bad you can't post a audio sample here just to show how easy and effective audition is but after all is it just 2017... |
#21
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Best way to remove mic feedback in post?
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#22
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Best way to remove mic feedback in post?
On Monday, December 25, 2017 at 9:29:43 PM UTC-5, geoff wrote:
On 26/12/2017 9:26 AM, wrote: Adobe Audition spectral editor all the way so easy just like lifting a layer off in Photoshop. Takes just a few min to get the hang of it but the easiest quickest way to get rid of any feedback and no affect the underlying track. By the time you use an FFT analysis and FFT EQ cut things up and batch em back i will have cleaned the whole track and have moved on. Too bad you can't post a audio sample here just to show how easy and effective audition is but after all is it just 2017... Or SpectraLayers The new wave of 2017!!! Actually, you can find Sony touting on YouTube about their Spectral stuff software. Shame Sony Music doesn't know how to use it!! Jack geoff |
#23
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Best way to remove mic feedback in post?
wrote:
Adobe Audition spectral editor all the way so easy just like lifting a layer off in Photoshop. Takes just a few min to get the hang of it but the easiest quickest way to get rid of any feedback and no affect the underlying track. By the time you use an FFT analysis and FFT EQ cut things up and batch em back i will have cleaned the whole track and have moved on. The honest truth is that what the Audition spectral editor is doing IS an FFT analysis and then FFT equalization, just with a convenient user interface. It is in fact an idea that was pioneered by CEDAR, and Audition adopted the basic design. These days, years after the post you're replying to, there are an awful lot of different options available. The days of riding the depth control on an Orban 622 in realtime are long gone. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." |
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