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Old 15 October 2016, 12:32   #65
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Join Date: Jun 2010
Location: PL
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Originally Posted by paul1981 View Post
I wouldn't get to obsessive with this. Signal to noise ratio does not tell you anything about the quality of a signal anyway, it only tells you the amount of noise. I suppose the real aim here is to try and ascertain whether there can be 14-bits of resolution. Whether your PC sound card is up to such a measurement I seriously doubt.

There is nothing obsessive at least not on my side - curiosity and rationality.
I like Amiga, music but i reject all audiophile hype and those magical HDMI cables that dramatically improve picture quality.
And if Amiga is 8 bit but capable to do 14 bit why then precisely described PC audio input with 2 - 10 bits more accurate electronics can't be used for perform measurements?
Most modern audio PC cards have more than 80...90dB quality - as engineer i think it is sufficient to perform such tests in home.
My goal is to use state of the art audio analyzer and do this in a way accurate as possible but anyone may do same things in home.
And distortions are always distortions even if some people likes them more.
Knowing that average Amiga has something like 65.43dB 'quality' will suddenly not kill pleasure of listening music and game fx on Amiga?
I really miss 8364R4 or R5 datasheet with such things specified clearly by Commodore.

Originally Posted by paul1981 View Post
Regarding it being unfair to compare Paula 14-bit at 44.1KHz with a cd, well it does a pretty good job I say. If you listen to it you'd agree too. No, it's not as good, due to NO oversampling, but it's bloody good - trust me.
And that's why i don't understand this rejection of idea to test - for me knowing that it is not 86 but perhaps 71 or 64dB will not kill any pleasure from Amiga sound.
And there is large group of people preferring non oversampled CD - they believe that oversampling killing CD audio... so called NOS DAC... they wish to pay hundreds and thousands of Euro for sometimes very ubiquitous constructions. They even building own math theory

Originally Posted by pyksy View Post
The filters in a1200 and a4000 do differ from older Amiga models. See for more information.
Thx, i know this and i use also this so overall circuitry can be modeled in SPICE.

Originally Posted by TroyWilkins View Post
I'm sure there are people here with the appropriate equipment to do this, so how about someone connect their Amigas sound output directly to a recording device, perhaps the mic in on their PCs sound card, and record the Amigas sound output while playing back various sounds, using different sound output configurations?
Nope, MIC input in PC is very bad idea:
- it is MIC input - very high gain means lot of noise,
- frequently is not linear but has non linear characteristic to deal with wide range of MIC signals (there is dynamic compressor there)
- it is MONO input
- it provide power supply for microphones as such it may have phantom voltage on pins - it should not kill Amiga but anyway will disturb quality.

You can use for audio measurement any LINE Input on PC - it should be quite OK. If you dob in Audio card quality you can use external player source (CD, DVD or decent portable player from reputable vendor with defined parameters).

Originally Posted by TroyWilkins View Post
Then these sounds could be examined in a sound editor, and we could all have a listen to the captured sound ourselves?
There is dedicated software for this:
And other very similar - not a problem.

Originally Posted by TroyWilkins View Post
Heck, we could even be really scientific about it, and have the captured sounds not labelled as to what they are, and see if people can tell by ear, this way we could even use the original sound at say 16-bit 44.1 kHz as a control? That sound converted to 8-bit 22050 Hz, converted to say 14-bit 22050 Hz, and the original simply converted to 16-bit 22050 Hz. That gives us 4 samples to listen to and compare, which is not an unreasonable amount in my opinion, and if it's short, say 15 seconds of audio, it should be enough to make a fair comparison.

So, what do we think of this idea? Any merit, or am I barking up the wrong tree?[/QUOTE]

I will try to do objective part (but need to wait for V500 or revive my A3000).

Last edited by pandy71; 15 October 2016 at 12:54.
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