Questions about sound artifact removal.

I am using Audacity 2.05 on 64 bit Windows 7 Home premium, with success.

I have been using the Centre Pan Remove Audio Effect on a Stereo .wav file. I have in fact found
that in terms of voice removal per se, I have met with great success. However, what I have
found is that there is a “digital dither” audio artifact which remains behind on my audio.

-Is it possible to converge upon and eliminate this dither artifact using the effects
ad capabilities of the v2.05 program to eliminate this dither, leaving nothing else but the
other sound components, behind background music and sound effects? Could
someone tell me how to proceed here?

-Failing this, could there be some algorithmic way to converge on the data transmitted itself,
ie by a known free plugin out there, or even by an api program accessing the sound stream?
I have successfully accessed the sound stream from my sound card’s driver output using
the java language, and would as a last resort wonder if there is a logical way to
find the artifact data, in a 256 bytes range?

If the question is can we make Vocal Removal perfect? Not so far. Most modern songs include stereo vocal effects and other left-right spacial modifications that escape Center Pan Removal because they’re not in the center.
Before and after.

The standard Vocal Removal is a packaged version of that thing on YouTube where they show you how to split stereo, invert one channel, etc, etc. The new removal tool does all that, but has extra filters so all the bass and drums may not go, too, but that’s about it.

As you suggest, this isn’t rocket surgery. Cancellation is a simple math problem. Anything further than that can be very entertaining.

There was a posting where Robert J. H. added some more functionality, but I can’t find that posting.

Vocal Removal makes it seem you can do so much better with just a little effort and that’s not true. Past the simple math, you run into the universal truth that we can’t split a mixed recording into individual instruments, singers and sounds. That truth is the killer of many sound shows. See #4.

The Four Horsemen of Audio Recording (reliable, time-tested ways to kill your show)
– 1. Echoes and room reverberation (Don’t record the show in your mum’s kitchen.)
– 2. Overload and Clipping (Sound that’s recorded too loud is permanently trashed.)
– 3. Compression Damage (Never do production in MP3.)
– 4. Background Sound (Don’t leave the TV on in the next room.)

Digital artefacts are frequently created through mp3 compression–it is not dither noise (I assume).
They are the result of rounding errors and alike. They only stay for a short time which corresponds to the frame size and are isolated peaks in the spectrum. Just like short, unmodulated sine tones.
Here’s a an example that I’ve encoded with a very low bit rate. You will notice that the artefacts disappear after isolating the center (what is common to both sides)

Removing vocals is quite the opposite, all differences are preserved including digital noise.
However, my Remove/isolate 2D Stereo Toolkit does sometimes out-perform the built-in voice removal because it works with 8192 sample chunks that do overlap by 5/7 or so. This can soften those tones a bit. Increasing the frame size (in a text editor) increases this effect too, but the down side is that you’ll get a longer reverb tail.
You should try my tool, it returns the center-free audio in stereo and thus the artefacts are less audible in general.

It would be an interesting project to make a “Digital Noise” filter, perhaps one of these days…

I have looked at these, particularly trying to lower and raise the bit rate (after applying the voice removal effect).

I find as expected that it is terribly easy to ruin all other sound by halving your stored bits and then going back to the higher containment rate.

Does anyone have a good number for a bitrate to drop down to, particularly since my primary rate is 48000 Hz?

Apart from this strategy, there would surely have to be a way to remove the digital artifacts voice removal introduces

to the audio track. Is there anything under way for the next version? Is there a way to use what comes with audacity,

or even a further free plugin, vst or any applicable other, that someone could give instructions about to

just swat the audio artifacts to 0, or unaudible?

For best quality ensure that you work in 32 bit float format. Look at the format information in the panel on the left end of the track. Note that due to limitations in some of the exporters, some file formats import in 16 bit. To change from 16 bit to 32 bit float, click on the name of the track (top of the panel on the left), then from the drop down menu select:
“Set sample format > 32 bit float”

I don’t think that we can advise how to deal with these “artefacts” as we don’t know precisely what you are referring to. It may help if you could post a short sample in WAV format so as to illustrate. See here for how to post an audio sample:

I’m just talking about the “squiggly” noise which is left after the vocal remover effect is run over audio.

Is there a way to hone in on these audio artifacts to remove them? Is there

a free add on or development on a new free feature which can work to remove these artifacts?

Which “Vocal Remover” are you using? The standard Audacity one as shown here?: Audacity Manual

Could you post a short audio clip in WAV format to illustrate the problem. Just a few second are needed. See here for how to post an audio sample:

I am using Audacity 2.05

The sound clip is personal use only stuff, so in fact I cannot post it.

I am using

[Menu BarEffectsVocal Remover (for center-panned vocals)…]

I do this, and found that while the vocals are successfully gone, there are artifact

“jiggle” noises now in its place. Since my audio track is so long, manual editing of the

data form is not an option, so I’m trying to find a way to eliminate artifact noises,

so that the speech vocals are removed (from convoluted audio), leaving music and

sound effects only, with no audio artifacts at all.


We wish you the best of luck with that. If you get something to work, post back and tell us how you did it. It’s a Forum for sharing ideas, not a Help Desk.


Artefacts can take any kind of distortion. They should be avoided in the first place because there’s simply no remedy for most of them.
This is especially true for audio sources like mp3. There’s aliasing, flanging tonal noise etc.
above all, the stereo image gets wishy-washy, the sound sources are no longer exactly defined.

However, have you tried my plug-in? Is the result better?
We can’t even make hazard propositions without any facts.

“We can’t even make hazard propositions without any facts.”

-What does this comment mean?

“However, have you tried my plug-in? Is the result better?”

-What does this comment mean?

It means that if we don’t know precisely what the artefacts are then we don’t know what the correct approach will be to deal with them. It’s like asking a doctor to make a sick patient well without allowing the doctor to examine the patient. Even with your written description, the “artefacts” could be any manner of thing. If we don’t know precisely what the problem is then any suggested “cures” are equally likely to make the problem worse. We may not know how to fix it even if we were able to examine the problem, or the problem may not be fixable at all, or it may be an easy fix. You could try using the Equalization effect that might fix it, but that is just a blind guess so I’d be surprised if it did work.

Robert previously suggested (Questions about sound artifact removal. - #3 by Robert_J_H) that you tried his plug-in. He is asking if you tried his suggestion and whether it produced a better result.