Aliasing Tests Ver 2.0

FractalAudio said:
D is not Digitech. I suppose you could say brand D is brand A/D, maker of that product that is a number.
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LOL
Might has well say it begins with a "D" ends with an "N" and has "IGIDESIG" in the middle :D

Anyway should we use a hicut filter after 10k to remove those aliasing that begins after it?
 
You can't remove aliasing with a filter. Once it's created you can't remove it without affecting the desired signal.
 
Hmmm alright.

But that audio information after 10k where the aliasing is on the AXE-FX II is "hearable" right? So there is room for improvement in the algorithms?
 
steadystate said:
While I suspect the aliasing would not be as noticeable in a real-world situation, it is unacceptable in an $1850.00 processor. Some people can detect very small levels of digital artifacts such as aliasing, quantization noise, and others that are correlated with the input signal. I had an early modeler that sounded like I had a synth playing a horrid duet with me.

Edit: Even lab tests are conducted in the real world. I should have said average Joe guitarist in a typical playing situation. I'd like to hear a high gain K profile, with the input being a single high note on the guitar neck slowly bent up and down. Based on this mp3, I would not be surprised if aliasing was audible. I wonder...
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My Boss GT6 used to alias to hell on bends, drove me loopy!

I love these kinds of tests, thanks Cliff.
 
steadystate said:
Edit: Even lab tests are conducted in the real world. I should have said average Joe guitarist in a typical playing situation. I'd like to hear a high gain K profile, with the input being a single high note on the guitar neck slowly bent up and down. Based on this mp3, I would not be surprised if aliasing was audible. I wonder...
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Don't even have to bend it. Here is brand K followed by the AxeII using matched presets between the two: www.fractalaudio.com/tmp/aliasing2.mp3
 
Maybe I have bionic ears but some sort of synthetic hiss localized around 10Khz always annoyed me with the axe ultra. Oh wait, I have bionic ears. Whatever .. I used to run a // notch at 9.8K until I found some settings that hide the hiss rather successfully. It's interesting to learn that this little part of the signal is hard to process. Interesting thread.
 
So my "Brand D" is doing a better job than my "Brand K" because of less aliasing.

But why to hell does "Brand D" not sound and feel as good as "Brand K"? Maybe because I'm using them with cabinet modeling?
 
I'm no expert, but I would imagine there's more to a quality modeler than a lack of aliasing. This is just one aspect to compare.
 
reminds me of a test of a ssl filter vst .. it hat no oversampling so the high filters had no effect on the 20k band under 44,1k .. although this is just a test it shows that not only the modelling is good it shows also the "technical homework" has been done very well by the axe fx II
 
AdamCook said:
Hmmm. That clip Cliff posted kind of sounds like the one I posted of our new sample rate reduction feature coming in v7.0 :).

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I actually burst out laughing when I heard that...

genuine out loud 100% LMFAO ! ! ! !

awesome.. made my day..
 
Cliff - those are really interesting results
especially the audio clips and how they reveal all the extra guck being added by the other units
 
I am a software guy, not hardware, so forgive me if my question is totally off base here, but:

You mentioned you used the Synth block within the Axe-FX to generate the source signal - would that not favour the Axe-FX in the tests as the clock speeds and processing rates are equivalent? Did you test the samples within the same Axe-FX unit as was generating the Synth signals, or did you 'chain' two units together, one as the source and one as the recipient?
 
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