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Old 12 October 2016, 22:08   #43
meynaf
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Join Date: Nov 2007
Location: Lyon / France
Age: 44
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Quote:
Originally Posted by pandy71 View Post
Nope it is not the same as Paula using Nyquist-Shanon and PCM and AY is non-PCM so there is tricky apporach for searching particular combination that corespond to linear sample value, SID is even more funny as they use internal triangle waveform to create 12 bit samples (of course they can use attenuator to form crude DAC)
I don't care about theorems. The Amiga outputs PCM and AY can be turned to output PCM as well, even though it's not designed for that.
Said otherwise, i care more about real life usage than pure theory.


Quote:
Originally Posted by pandy71 View Post
Nope both partially overlapping so there is maybe 65535 but only 16383 are usable and after calibration there is even less.
Here you take as granted that we go to 14bit before calibration.
This is just not the case !


Quote:
Originally Posted by pandy71 View Post
Nothing but more or less we are closer to one of my first statement - IMHO 14 bit Paula will be after calibration close to 10 - 12 bit depends on calibration accuracy, DAC accuracy and power supply quality.
Same problem as above. We would perhaps get 10-12 bits if we took 14 bit and then calibrate on them.
But we take 16 bits as input and calibrate just that, ending with 14 bits.


Quote:
Originally Posted by pandy71 View Post
Which Amiga (mostly motherboard revision).
It was an unexpanded A600 (labeled A300, i don't remember other details). I don't have it anymore.
I've never plugged my A1200 to something really big, but i've never heard any noise coming from it either.


Quote:
Originally Posted by pandy71 View Post
In modern PC analog audio power section design is usually very well designed (separate analog ground plane, linear regulator, way better Vref etc)
But nevertheless the amount of noise it receives from other components is way bigger...


Quote:
Originally Posted by pandy71 View Post
Well trust me - most of them, even cheap players from China can provide 92 - 98dB SNR.
Yeah, on the paper. But the mere fact they are 16 bit doesn't mean they really provide 96dB. They might have very poor signal/noise ratio and end up with 12 bit quality.


Quote:
Originally Posted by pandy71 View Post
I understand where is difference between us - you see this purelly from arithmetic perspective and for you this is just code that operate in deterministic way and always provide same result for same data - from my perspective electric current is not so simple. Please understand difference between DAC resolution and DAC accuracy - this is completely different - very frequently there is specified something like ENOB https://en.wikipedia.org/wiki/Effective_number_of_bits - it is not uncommon to find for example 10 bit ADC that offer ENOB like 6.4 bit and there is nothing wrong - this is nature of electronics.
http://www.analog.com/media/en/train...als/MT-003.pdf
And ? Calibration is there precisely to raise accuracy, not resolution.
In addition, don't forget that the sound doesn't come directly from the DAC, there is filtering hardware behind. And what matters for me is the final output.


Quote:
Originally Posted by pandy71 View Post
It may look very bad but real 12 bit is IMHO very good result.
If so, why the heck would true 16-bit DAC be better ? They're not linear either.
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