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MQA spectrum plots


mansr

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Am I viewing the 10kHz sine wave graph correctly to show all else but the 10kHz signal is -100db or lower? (For the 20kHz graph - wow!)

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Am I viewing the 10kHz sine wave graph correctly to show all else but the 10kHz signal is -100db or lower? (For the 20kHz graph - wow!)

 

It is not correct input signal. Just the research how the codec react to different input signals.

 

If input signal correctly coded the codec should work correctly.

 

Now need encoder for full research.

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It is not correct input signal. Just the research how the codec react to different input signals.

 

If input signal correctly coded the codec should work correctly.

 

Now need encoder for full research.

In what sense is a 10 kHz sine wave not correct?

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In what sense is a 10 kHz sine wave not correct?

 

For pure experiment need to check coded 10 kHz.

 

I'm programmer, and I doubt everywhere ;-)

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I don't have an encoder, so I can't do that.

 

I know it.

 

 

Still, any audio processing that mangles a trivial signal this badly raises some doubts.

 

Possibly bug there. Possibly - not. We can suppose only, how it must work.

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I don't have an encoder, so I can't do that. Still, any audio processing that mangles a trivial signal this badly raises some doubts.

 

Is it really a fair test to input a non-encoded signal? I'm really digging your spectrum plots, but without understanding precisely what the encoder does, pumping a sine wave into the decoder is a meaningless exercise IMHO.

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Sure, it could be a bug, but then everybody is listening to this bug.

 

Try sweep sine or 10010, 10020, etc.

 

Possibly there FFT grid to measured sine frequency issue.

 

For analysis of sweep sine need to look to time-frequency spectrum diagramm.

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Try sweep sine or 10010, 10020, etc.

 

Possibly there FFT grid to measured sine frequency issue.

 

For analysis of sweep sine need to look to time-frequency spectrum diagramm.

The same FFT of a 10 kHz tone that hasn't gone through the MQA decoder looks fine.

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Sure, it could be a bug, but then everybody is listening to this bug.

 

Is there another set of MQA codec software that you or someone else could test with the same file?

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The same FFT of a 10 kHz tone that hasn't gone through the MQA decoder looks fine.

 

Got it. But if you will have time, would be interesting reaction to sweep sine.

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pretty. what does that represent and what does it show? thanks for the education

 

It's a spectrogram of a sine sweep 0-22.05 kHz. It should show just a single line from the bottom left to the middle of the right-hand edge. What we see here is lots of aliasing and distortion products. It may be pretty, but it's wrong.

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Is it really a fair test to input a non-encoded signal? I'm really digging your spectrum plots, but without understanding precisely what the encoder does, pumping a sine wave into the decoder is a meaningless exercise IMHO.

 

I would say so too.. How can you judge what MQA is actually outputting when all you have is the decoder side of the process?

It's like reading the last chapter of a book and judging the full story without reading the first three chapters.

 

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It's a spectrogram of a sine sweep 0-22.05 kHz. It should show just a single line from the bottom left to the middle of the right-hand edge. What we see here is lots of aliasing and distortion products. It may be pretty, but it's wrong.

 

Right, the "decoder" portion of this evidently goes for minimizing pre-ringing at the expense of allowing a lot of aliasing. So unless aliases were removed in encoding....

 

 

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One never knows, do one? - Fats Waller

The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of true art and true science. - Einstein

Computer, Audirvana -> optical Ethernet to Fitlet3 -> Fibbr Alpha Optical USB -> iFi NEO iDSD DAC -> Apollon Audio 1ET400A Mini (Purifi based) -> Vandersteen 3A Signature.

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Have you read from the start of the thread? Mansr posted spectrograms of original DXD, non-decoded MQA and decoded MQA files. Presumably the MQA files were encoded on the encoder side!

 

I get it now, thanks for clarifying.

 

But I still think that to be able to really analyse what MQA is doing one should in fact be able to compare the actual input of (and before) the encoder with the output after the decoder. I understand now this is hard or impossible to achieve and therefore a DXD file has been used for comparison.

 

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