Soundtoys 6 - What would you like to see?

[egbert]

@ jens
My comment isn't that "Decapitator really sucks" - it might be fine for most use cases although its clearly better at 96 kHz. I actually went looking online for evidence that showed that it used over-sampling - my reasoning being that a distortion plugin would be the most likely to use it (see my link a few posts back in this thread to Erik Klein (Digital Igloo) from Line-6 on the need for fairly extreme oversampling (ie 16x) for acceptable modelling of guitar amp distortion and, I assume guitar pedal distortion which the Helix platform does rather well).

Anyway, my search came up with that page I linked to which showed that actually there is simple foldover aliasing in Decapitator at 44.1 kHz. I am treating that test as being diagnostic of a lack of oversampling.

In case this is all greek to anyone - distortion by definition is harmonically related - so distortion of a 10 kHz signal will include peaks at 20, 30, 40kHz and so on. The 30 and 40 kHz peaks will foldover back into the audio band once they cross the Nyquist limit = (sampling rate)/2. So you will get a aliasing peak at ~14 kHz (22kHz - 8kHz). This peak is not harmonically related - it is noise - hence aliasing noise. Oversampling changes all this because instead of the Nyquist limit being just above the audio band at 22.05 kHz it could be way up at 384 kHz (16x OS starting from 48 kHz).

[c_voltage]

It seems to me that the aliasing factor is overrated so much. In terms of sound quality of the final product.
But each has its own priorities, of course.

[egbert]

It seems to me that the aliasing factor is overrated so much. In terms of sound quality of the final product.
But each has its own priorities, of course.

Well, gee c_v ... what does quality mean, in your book? (There's a book all about that btw - check out Zen and the Art of Motorcycle Maintenance).

I think water quality - for example - is often connected with how much undesirable adulterant is added to what you are drinking - good quality drinking water has a minimum of ordure floating in it, for example.

Aliasing noise, is hash - it is noise that is unrelated to the program material. It is like what you get when you turn an old analog TV to a non-existent channel. You are mixing some amount of that nasty shit in with the music. Less of it equates to better quality for most people.

It seems, then, that the amount of aliasing noise is DIRECTLY related to the perceived quality of the signal. Almost by definition.

[Scotty]

[quote=egbert post_id=7499226 time=1566664557

It seems, then, that the amount of aliasing noise is DIRECTLY related to the perceived quality of the signal. Almost by definition.
[/quote]

I guess if what is generating the sound is that uninteresting then you might start to listen for these artifacts with more acute hearing... otherwise I think the concerns are overstated.

[Rockatansky]

Aliasing noise, is hash - it is noise that is unrelated to the program material.

Uhm, no. Non-linear processes that change the shape of the waveform (compressors, distortion, ...) create harmonic overtones of the original and add them to the signal. So aliasing is totally related to the program material. It would not exist without it, and it is created at multiplied frequencies of the original. In fact, at frequencies so high up that they surpass Nyquist (1/2 sample rate in Hertz) and can not be correctly placed in the signal, simply because they would require a higher sample count to be correctly placeable in the audio stream. Since there aren't as many sample slots available as would be required to store those frequencies, they get -incorrectly- stored in sample slots that actually are available, which is that "folding back into the audible spectrum" part. Aliasing isn't just some noisefloor that magically appears due to "bad quality" of something. It is harmonics of the original in a frequency range above Nyquist that cannot be correctly handled, so it gets placed at incorrect frequencies below Nyquist instead. Oversampling provides more samples, makes it possible to correctly calculate and store those higher-than-original-Nyquist frequencies, and the filters used in oversampling remove them accordingly so that they don't fold back into the audible spectrum. Aliasing, incorrectly placed images of the original signal's frequency spectrum, can be mimized or completely removed by oversampling. Alisasing can cause resonances where mirroring frequencies stack on top of original frequencies, and it can cause volume changes by potentially phase-cancelling out original frequencies. Aliasing is very related to the original signal.

It seems, then, that the amount of aliasing noise is DIRECTLY related to the perceived quality of the signal. Almost by definition.

By definition it is, not almost. Not removing aliasing overtones by oversampling leads to pollution of the audible spectrum, unlike to anything that would happen in the real, analog world. The result of oversampling is a signal that sounds the way it should sound, or at least closer to what it would sound like in the real world.

[cryophonik]

Sound toys needs to grow more in sound quality, i think it offer great experimental approaches, but it doesn't sounds PRO at all.

Ah, yes, that makes sense; a company with one of the longest pedigrees in digital sound effects processing, which includes the designers of the Eventide H3000, don't know how to sound 'PRO'.

Sounds legit.

Please remind us all again what the metric for 'PRO' is?

Dude just joined KVR and has 6 posts. I wouldn’t take him seriously.

[Aloysius]

Professional
A professional is a member of a profession or any person who earns their living from a specified professional activity.

[Halonmusic]

Get rid of iLok

[Aloysius]

Get rid of people who complain about iLok

[Halonmusic]

No!

[Aloysius]

YES!!!

[egbert]

@ Rocktansky - your logic is flawed. If you promise not to get mad I will explain further mmkay?

The aliasing frequencies are not related to the frequencies in the program material. They are an artifact of its processing in the digital domain. You mostly tried to explain back to me what I explained in my previous posts about the creation of aliasing noise in more verbose form. When we say something is related we mean it is in the same family - mathematically speaking - and that family is a set of multiples of a fundamental frequency.

An aliasing peak at ~14khz is not related to the 10 kHz source material. Without the 10 kHz source being processed by Decapitator it would not have been born so you could argue that the 10 kHz source waveform was necessary for the formation of the aliasing peak but it is not related mathematically - it is outside the harmonic series.

[reggie1979]

Frankly, I asked others to comment on "aliasing" with soundtoys plugs and got NOTHING.

Again, for those bitching about this, can someone please respond with real world examples? Otherwise, shut up:

Be bold or be quiet. I (and others) don't know what to think w/o examples

[egbert]

@reggie - Dude, you are coming across as a leetle bit proprietorial 'bout this discussion but you ain't even the OP? Echoboy with saturation cranked up would be the best way to generate aliasing. It is the distortion generating processes that will create higher harmonics and push your source material which is probably band-limited above nyquist. To demonstrate it run a test signal through it and look at the output in a signal analyzer. Whether you care at all about this from a musical point of view is up to you - Echoboy has never offended me as a noisy mess and if you want clean then a clean algo is a good choice.

If you want a serve of tape distortion with your delay then you probably don't need a side dish of aliasing with it. So evaluate the tape delay sounds from Echoboy side by side with those from Valhalla delay or one of the other products and see which sounds better to you with your application.

[perfumer]

If you want a serve of tape distortion with your delay then you probably don't need a side dish of aliasing with it.

Aliasing is garbage that you don't need. What's so difficult to understand about that?