Hi, anyone knows a plugin to remove noise already recorded tracks for use in ardour?
Nothing that's good enough to actually use.
I don't know if that's appropriate on these forums to speak of another program, but I did this kind of thing with Ardour just a few days ago to clean very bad audio recorded with the crappy integrated sound card of my laptop.
I used the noise removal effect: http://wiki.audacityteam.org/index.php?title=Noise_Removal
And it worked pretty well. So obviously the best is to have good hardware (sound card, microphone, etc.) so that you don't have to clean anything; but other than that, it is a nice use of Audacity.
Now I don't know much about Ardour or any other program (not even about Audacity). I am not a professional audio guy, so my opinion is worth what it's worth. :-)
The short is it doesn't come close to comparing to professional solutions, it is vastly better than it was a few years ago yes, but still not much of a comparison.
But if quality isn't that important, then go ahead and give it a shot;)
seablade: I have no other professional tool to compare, but if you say so. :-)
What is the reason for this? Are the good noise cleaning algorithms all under some patents so we don't find any of the good ones in FLOSS tools?
In any case, I imagine that if professional quality is that important, one would not record with low quality hardware from the start (well I guess I actually do see one case where you want to do this still for professional reason: when you want to recover very old recording, of high artistic quality).
Sophisticated NR plugins require a substantial investment of time and resources, to do right, and no one has been willing to do that, yet.
If it is just hi-freq-noise, what about an equalizer?
@Ricardus: Any plugin requires a substantial investment of time and resources to do right :)
"noise" is a pretty vague term.
Look at http://www.cedar-audio.com/ for a broad range of techniques for dealing with different problems that can all be described as "noise". (None of them is free, though)
The noise removal plugin that comes with audacity is good for tape hiss, AC power hum or anything else with a constant level and frequency. It works by subtracting the noise spectrum from the signal. It's useless for many other types of noise. I don't know if that can be made to work with Ardour.
Reducing randomly timed clicks and crackles like those on old vinyl records can also be done effectively by a quite different technique, and there are many software tools dedicated to that function.
Gnome wave cleaner http://gwc.sourceforge.net: it's a standalone program and it does a good work
GWC tends to suffer from the, "It may be good but dang if I can figure it out" side of things. I haven't actually heard good results that compare to Izotope RX2 for example out of it.
Wasn't ignoring your question by the way, but others have touched on it, do you want me to go into details still?
Yeah, I have yet to get GWC to do anything but crash on large WAV and AIF files.
When I have tried smaller files, and it didn't outright crash, I couldn't get anywhere near the results that the author shows in his demos.
I had to compile GWC from source and tweak a little bit to get it, but I did a good work restoring an old cassette tape. You can't edit, cut files with it because it crashes a lot (I used Audacity for that), but I could remove a lot of hiss a clicks better than audacity.
Hi, this was a good start for me:
... under: Documentation > Tip > LADSPA Noise Removal.
Hope it helps.
I haven't tried this but I was reading that if you leave some "silence" on your track and select a segment of it (that has a guitar hum or whatever noise you're trying to get rid of) then copy it to a new track and duplicate the copied region so that it fills the same time frame as the other track. Then you can reverse the phase on the second track and it should cancel out the noise in the first track.
That "reverse phase" cancellation doesn't work. The copied 'noise' won't correlate with the noise you are trying to cancel, so you'll end up just adding more noise. I think somebody has misunderstood the Audacity noise reduction tool I descried in an earlier post on this thread, which does take a sample of the pure noise, but then does something much more sophisticated with it.
If it's a very constant frequency hum or other periodic tone, you might be able to adjust the timing do do it that way, but it would be very tricky and unreliable (half a cycle out and you're DOUBLING the noise!) and you're probably much better off with a sharp notch filter or delay+invert set to 1 period of the tone you wish to cancel in that case.
Maybe you should first locate the noise-source.
Probably a noise reducing plugin for Ardour would not be the ticket at all.
Does the noise come from your (maybe even analog and not yet sampled) audio source?
Does the noice come from Ardour?
Is the noise reasoned by some signal-source behind Ardour?
So far I know is the noise-distance even in the cheapest audio-cards far away from bad.
The software or the switching of registers doesn't (so far I am right) lever the noise as well so you are probably working with quite a good signal/noise ratio as is.
I'd check your equipment and in particular cable-connections.
Tremendues noise can result from bad connections, cold soldering etc.
PS: any additional plugin in the chain (even hypotetically) adds another noise-source, we are clear about that right?
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