Fractal Talk

FractalAudio said:
Whether someone can hear aliasing or not is complicated. It's a psychoacoustic thing.

It depends on the exact nature of the aliasing. When the Kemper first came out the aliasing was very noticeable because the aliased tones occurred in the midrange when playing higher notes. If the aliases are near the distortion products they are masked by a phenomenon known as perceptual masking. This is the same phenomenon that is the basis for MP3 encoding. Humans can't hear quiet tones that are close in frequency to loud tones.

As with all engineering problems it's a trade-off. To reduce aliasing you can either increase the sample rate (via oversampling, for example) or use Antiderivative Anti-Aliasing (ADAA). Both of these approaches increase the amount of CPU required. Simply oversampling is very effective but doubles the amount of CPU cycles.

ADAA can achieve aliasing reduction but it's no free lunch either. The problem is the antiderivative is typically a more complex function, sometimes much more complex (tanh(x) becomes log(cosh(x))or example). For example if the function is, say, x^2, the anti-derivative is 1/3*x^3. This requires two extra multiplies. You might as well simply double the sample rate. Then you have to take do a difference and if the difference is near zero you risk generating a result that exceeds the numerical range so you have to add conditionals which slow things down even more. ADAA also doesn't work for nonlinear systems with memory. Nearly all our algorithms employ memory so we don't use ADAA.
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Wouldn't doubling the sample-rate require upsampling filters and downsampling filters, and have more CPU impact than ADAA? Wouldn't SIMD help with the CPU impact of of ADAA as well?
 
FractalAudio said:
Yup, he's a wingnut. I call him a "sociomediapath".

Aliases:
Jean Bloomberg
Yvan Bloomberg
Yvan Apothekar
Stainless Steel Frets
Shattered Square
Elon Mask
Popstar
and maybe Dada.
Click to expand...

oh man.... and the rest :ROFLMAO:

some bonus funny ones:

Francois NeuralNet
MXR ROCKMANN - (was allegedly messaging a few industry types, pretending he was the official MXR brand)
Mark Nembrini
RichSwissGuy

....and really quite worrying and disturbing:

last year I caught him pretending to be some young innocent girl from Canada =(

he's definitely a "sociomediapath", but I have firm reasons and evidence to back it up, that he's a lot worse than that
 
Last edited:
FractalAudio said:
Yup, he's a wingnut. I call him a "sociomediapath".

Aliases:
Jean Bloomberg
Yvan Bloomberg
Yvan Apothekar
Stainless Steel Frets
Shattered Square
Elon Mask
Popstar
and maybe Dada.
Click to expand...
Wasn’t Shattered Square at the peak of Mt Stupid a few years back ?
 
blandified said:
Right but if they fixed the issue with the amp block aliasing, what changes in the Drive block needed to be made that results in less aliasing?
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There are other functions in the Fractal ecosystem that provide a choice between normal and higher oversampling. Such as the preamp in the Cab block, and the amp modeling itself. There's another one, I think, but I can't recall it right now. Anyway, normal suffices, but it simply is an option for the OCD crowd to go for ultra.
 
Orvillain said:
Wouldn't doubling the sample-rate require upsampling filters and downsampling filters, and have more CPU impact than ADAA? Wouldn't SIMD help with the CPU impact of of ADAA as well?
Click to expand...
We already upsample and downsample. You have to upsample and downsample at least 2x when distorting, otherwise the aliasing is objectionable. For heavy distortion at least 4x is desirable.

SIMD may or may not help, probably not. Even if it did it would also help in the non-ADAA case so it's not a gain.

Regardless, ADAA doesn't work in our algorithms because almost all our algorithms use memory (which is why they sound good). Analog circuits have memory, even if there aren't explicit reactive components in the network. For example, a tube triode with just resistors connected to its terminals still exhibits memory effects due to parasitic capacitances (Miller effect).
 
FractalAudio said:
We already upsample and downsample. You have to upsample and downsample at least 2x when distorting, otherwise the aliasing is objectionable. For heavy distortion at least 4x is desirable.

SIMD may or may not help, probably not. Even if it did it would also help in the non-ADAA case so it's not a gain.

Regardless, ADAA doesn't work in our algorithms because almost all our algorithms use memory (which is why they sound good). Analog circuits have memory, even if there aren't explicit reactive components in the network. For example, a tube triode with just resistors connected to its terminals still exhibits memory effects due to parasitic capacitances (Miller effect).
Click to expand...

Now you got me thinking... do you consider physical setup/CCA layout in your models?

For example, trace geometry in a CCA... maybe a 10mil trace over a GND plane with some dielectric height will have some sort of capacitance. Something in the order of pF, but still.

I have been doing a lot of layout and signal integrity/power integrity for work using Hyperlynx and we have to consider all that fun stuff.
 
blandified said:
Now you got me thinking... do you consider physical setup/CCA layout in your models?
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IIRC, he explained how they DO and how, for example, the tube socket material and the like makes a difference or has effects.

Found the post:
F

Post in thread 'The technical modelling thread'

You rarely, if ever, need sin or cos for amp modeling. More common trig functions encountered are tanh and atan. I personally am not a fan of LUTs but use them when necessary. I prefer polynomials when possible.

There are many different techniques for nonlinear modeling (which is the crux of the issue). If the circuit is linear you can simply use linear digital filters.

There are nodal techniques: K-method, DK-method, modified nodal analysis (MNA), etc. SPICE is an example of MNA. Wave Digital Filters (WDFs) are another technique and are a type of scattering method.

Regardless of...
  • Like
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  • Mind Blown
 
State of Epicicity said:
What the fuck is a camp survivor?
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1772629697051.png
 
From our own Drew from the FAS Forum

It’s just a term some of us have given to the people that have some pretty bizarre hatred for FAS or Cliff. There is no real camp, but somewhere along the way in these people’s lives, they had a bad experience. Perfect example was the guy who came here last year and was mad about the big mod wheel not scrolling through presets from the home screen the way he thought it should. He couldn’t let it go that he was just using the wheel the wrong way, so he sold his unit and now bashes Fractal every chance he gets on every forum he’s on like he gets paid to do so. Prime example of a Fractal Camp Survivor.

They all have their stories and very much need them to be heard by anyone willing to listen. The unfortunate thing is, you mix these guys up with the guys who came here for legit advice and received a more condescending reply and don’t come back again, those two groups of people have no problem explaining their experiences here and it doesn’t bode well for the community overall. This place takes a lot of heat on the majority of forums I post on, some grounded in reality and some only in the mind’s of the Survivors.
 
DrewJD82 said:
There’s no way the EU hasn’t done away with lead paint yet, but here we are.
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Not sure what this statement is supposed to mean (I’m not from EU/US), but almost everywhere in the world the phrase “camp survivor” usually refers to someone who survived the Holocaust. That was the source of @State of Epicicity ’s question, I think. And frankly, using a term like that to refer to trolls is a tad disingenuous, regardless of how tacky said trolls might be.

That’s the end of what I have to say about this.
 
saarangnarayan said:
Not sure what this statement is supposed to mean (I’m not from EU/US), but almost everywhere in the world the phrase “camp survivor” usually refers to someone who survived the Holocaust. That was the source of @State of Epicicity ’s question, I think. And frankly, using a term like that to refer to trolls is a tad disingenuous, regardless of how tacky said trolls might be.

That’s the end of what I have to say about this.
Click to expand...
I always viewed it as:

Band Camp members always needing to let people know they went to band camp, even when nobody asks

american pie this one time at band camp GIF by IFC
 
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