Anti-Aliasing plugin

[BertKoor]

Now I'm 90% sure you're looking for a noise reduction plugin, and not anti-aliasing. Search for noise reduction, it's the same principal as I've described above. Guarantee: push it too far and it sounds like shit.

theres a possiblity that the quality of some synths will come into question..

Thanks for your concideration, because we had a wespected synth developew of a vewy good synth go ballistic because there was pwoof his synth had sevewe aliasing pwoblems.

If you're truely trying to cure aliasing, then please contact the developer about the issue. We all will benefit of the improved version! WilliamK did fix it at the end...

[Lagrange]

jupiter8: So this is aliasing then.. man oh man..

[Lagrange]

Ok guys I gotta get to work I will try noise reduction and oversampling for now and see what happens..

[dreamkeeper]

dreamkeeper: Yes that makes more sense.. So these guys dont know what there talking about??

http://www.jxplugins.co.uk/index.php3?p=5

I'm pretty sure they know their stuff. However it seems to me that the descriptions are oversamp... err.. oversimplifying a bit. Also the spectrums seem a bit um... hyped, in order to make the point.

See, I didn't hear the sounds, so I made assumptions about the nature of the signals. Which is exactly the point: you cannot decide what the signal was intended to be without actually knowing the intention. The most interesting sounds are often the most complex ones in regard to their harmonic content. It's not straightforward, like you could say this harmonic is important and that one isn't. Often the weak harmonics actually make the sound what it is. If you concentrate only on the strongest ones, you're in danger to end up with sterile sounds.

So, no, I don't think it is possible. And this...

Let me put the question this way.. Is there a plugin that would take me from this:

to this

...is a very special case imho.

[Aleksey Vaneev]

Lagrange, no plugin will make that... Aliasing if it was created, becomes a part of sound.

[Torben]

Lagrange, no plugin will make that... Aliasing if it was created, becomes a part of sound.

I would be careful what I say. 20 years ago I swore it was and would always be impossible to remove specific noise from audio, but now it is possible to fingerprint noise and remove it.

Torben

[dreamkeeper]

20 years ago I swore it was and would always be impossible to remove specific noise from audio, but now it is possible to fingerprint noise and remove it.

Yup! "to fingerprint" being the key here.

[Torben]

20 years ago I swore it was and would always be impossible to remove specific noise from audio, but now it is possible to fingerprint noise and remove it.

Yup! "to fingerprint" being the key here.

New techniques are invented every day so one must never say never.

Torben

[93143]

There are two possible sources of aliasing-type noise (assuming adequate bit depth) - frequency foldback and imperfect interpolation. The latter shouldn't occur with a pure synth, but with samples it can be a problem, depending on the software you use.

For a synth sound, I suppose you could try to identify the sequence of the harmonics and figure out which ones were likely to be foldbacks from the extension of the sequence rather than part of it. If you had complex sampled or non-tone sounds, this would almost certainly cease to be possible. Just having more than one note at a time would throw a wrench in the works, never mind more than one oscillator or even synth. In addition, it doesn't account for extra harmonics generated by poor interpolation.

This might be considered a form of decision-making AI; certainly not the same thing as noise removal. Human ears can pick up on noise fingerprints easily (barring volume masking) without exercise of judgment, but only in specific cases can we tell what is aliasing and what is not.

You never quite know with applied computer science. Torben (who is much more of an expert than I am...) may have a point.

[Lagrange]

Thanks everyone for help on this.. I think I have a better understanding now..

[Aleksey Vaneev]

Lagrange, no plugin will make that... Aliasing if it was created, becomes a part of sound.

I would be careful what I say. 20 years ago I swore it was and would always be impossible to remove specific noise from audio, but now it is possible to fingerprint noise and remove it.

Torben

Show me.

No, honestly, do you think fingerprinting will help here? You are showing signs of wishful thinking I suppose. Or you are talking about removing aliasing produced from a pure analytic sinewave...

[DevonB]

Thanks everyone for help on this.. I think I have a better understanding now..

What really WOULD be helpful would be to tell us exactly what you're working with and what you're trying to accomplish? You were very vague in your first post. We can tell you 'stuff' when you ask about 'stuff', but it becomes a lot of garbage 'stuff' without the details.

Devon

[Torben]

Lagrange, no plugin will make that... Aliasing if it was created, becomes a part of sound.

I would be careful what I say. 20 years ago I swore it was and would always be impossible to remove specific noise from audio, but now it is possible to fingerprint noise and remove it.

Torben

Show me.

No, honestly, do you think fingerprinting will help here? You are showing signs of wishful thinking I suppose. Or you are talking about removing aliasing produced from a pure analytic sinewave...

I do not have a technique for this. I just said that this might sound impossible for us now, like removing noise did 20 years ago, but in the future someone might come up with a way. Remember that Alias is not random noise but can actually be described exact mathematically, so when analyzing an audio signal we know exactly where the aliased components will be as long as we know the original sample frequency. The "simple" way would be to dynamically notch out the entire potential alias frequencies; it would maybe not be transparent but it's a start. It should be possible to make such a plugin

Torben

[Alex@SE_]

The easiest way to remove the main audible aliasing
would be HP-filter to cut all frequencies below
played note frequency. E.g. this filter should be dynamic and managed by input midi-notes.

Next step to further remove in-sound aliasing distortion would be comb-filter to
eliminate non-harmonic content of the synthesized note.

--Alex

[stefancrs]

Here's a neat example:
A pure 9kHz sine wave
Now remove the aliasing
What to do?