digitalscream
Member
Hmmm...this strikes me as a pretty flawed "study", because it glosses over some hugely important facts.
- Where's the control? I mean...you're right that analogue amps don't alias, but they *do* produce noise outside the the desired response to the input signal (background hiss, hum etc), especially at high gain settings, and it's most definitely audible.
- What were the settings for the two amp models (ie was it apples-to-apples)? Were they functionally identical (ie sound the same), nominally identical (the same number on the dial) or neither? This is relevant, of course, because TrueRTA doesn't just measure aliasing - as evidenced by the presence of the ground loop hum in both of the Fractal units' response graphs.
- The setup was clearly not apples-to-apples for all units, since both of the Fractal units appear to have a ground loop. Unless we're supposed to draw the conclusion that Fractal gear is more susceptible to ground loops than the competitor in question...?
- The threshold of hearing is not constant for all human beings. Women have a significantly lower threshold than men, and the threshold can increase by up to 60dB with age.
- The threshold of hearing is somewhat variable even when controlling for a single human being...for example, where it's around 60dB for a 30Hz tone (young folk in their early 20s - I picked these because they're the ones who'd be able to hear that "important" 18kHz spike...unlike most residents of musicians' forums, myself included). Up in the 10kHz range it's closer to 18dB, which means all three units should have audible aliasing. The reason they don't is that tone duration makes a massive difference (the shorter the duration, the higher the threshold), so sweeping the input wave muddies the results significantly.
- Where's the control? I mean...you're right that analogue amps don't alias, but they *do* produce noise outside the the desired response to the input signal (background hiss, hum etc), especially at high gain settings, and it's most definitely audible.
- What were the settings for the two amp models (ie was it apples-to-apples)? Were they functionally identical (ie sound the same), nominally identical (the same number on the dial) or neither? This is relevant, of course, because TrueRTA doesn't just measure aliasing - as evidenced by the presence of the ground loop hum in both of the Fractal units' response graphs.
- The setup was clearly not apples-to-apples for all units, since both of the Fractal units appear to have a ground loop. Unless we're supposed to draw the conclusion that Fractal gear is more susceptible to ground loops than the competitor in question...?
- The threshold of hearing is not constant for all human beings. Women have a significantly lower threshold than men, and the threshold can increase by up to 60dB with age.
- The threshold of hearing is somewhat variable even when controlling for a single human being...for example, where it's around 60dB for a 30Hz tone (young folk in their early 20s - I picked these because they're the ones who'd be able to hear that "important" 18kHz spike...unlike most residents of musicians' forums, myself included). Up in the 10kHz range it's closer to 18dB, which means all three units should have audible aliasing. The reason they don't is that tone duration makes a massive difference (the shorter the duration, the higher the threshold), so sweeping the input wave muddies the results significantly.
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