Rex
Legend!
The alternating current coming in through the power plug gets rectified to turn it into direct current that the circuits can use. Rectification results in a signal that's rich in 3rd-order harmonics. The 3rd harmonic of 60 Hz is 180 Hz.
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Ooooh... Charts and Graphs
- Thread starter FractalAudio
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Rex
Legend!
Correct. It's the nearly-inaudible (-63 dB) result of a ground loop between the equipment.
guitarmike
Experienced
Thanks Yek! As usual, you present timely and helpful info for the community once again. Upon studying up on this subject, I realized that this old man had forgotten some stuff!!! I find most electronics to be fairly intuitive, but the digital conversion process, not so much.There is also a ton of bad info out there on this subject. It is a good thing that we have a company that does understand this stuff and offers its customers real information and products void of ignorance and hype. In a world full of bullshit, I find Fractal Audio to be quite refreshing.
nicolasrivera
Fractal Fanatic
jlglespaul
Inspired
I am always amazed when a new firmware is released, i do not understand the technical side, although years back my tech would try to explain his mods. What i do understand is you can hear how this affects the string and chord characteristics that seem to breath with clarity and respond more naturally . . . sounding more like a beautiful animal. A big thanks to Cliff . . i never thought i would be playing something other than my Marshall 800 . . you've opened a new world of fidelity for all of us.
rodzimguitar68
Fractal Fanatic
He's not a Fractal employee....he just plays one on the Forum?
rodzimguitar68
Fractal Fanatic
@ Cliff, why are the readings for Fractal lower than the "other" until the 10K explosion? Is this an indicator of idling quietness?????
BillyZeppa
Power User
If I may, it's not idling noise. It is a form of distortion that results only when a signal is present. It is way lower than threshold of hearing for almost all of the II graph, and all of the III graph.
This is meant to show better aliasing performance. Aliasing isn’t idling noise, it’s a set of nasty unmusical seemingly random frequencies which are, however, a product of the sound being played. You may not discern them but they make things sound like cheap digital crap.
The way to fight aliasing is oversampling, running effects internally at higher sampling rates, which costs CPU cycles.
So that “competitor”, judging by the file name, is Helix. It has the same type of DSP chip as AX8, but lets you use more effects simultaneously. More effects means more CPU cycles, so there’s a trade off. Line 6 apparently sacrificed oversampling. That’s why you have less crap in the top end in Axe-FX.
No. Apparently people aren't understanding what the graph means.
The stuff from 9-11K is the INPUT SIGNAL. The stuff at 18K and up is harmonic distortion (desirable). Everything else is aliasing (undesirable).
yeky83
Power User
Wow, file name... nice detective work!
180 Hz is ground loop, so not everything is aliasing, apparently.
I don’t understand the graph, or at least much of it. Beside the ground loop, there’s all this noise at -80 dB or so - it can’t all be aliasing, can it?
But for regular noise, there’s too much of it, where did all the dynamic range go?
Also, the graph shows dBu - what does that even mean in the digital domain? Or is it measured at output, after D/A conversion?
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Tuco
Inspired
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