In defense of QRONO d2a?
To be clear, this is just a scientific approach. I'm not sure it's even audible, but seeing these results was worth sharing.
I'm having trouble with doing a blind test. When I volume match in Audacity and save a FLAC, it increases in size tremendously even though I have dithering off, which prevents me from attaching the files to the post.
Test CD: IASCA 2023 Reference CD
2 Disc set with 'Evaluation' and 'Entertainment' CDs and liner notes. This CD includes music and test tracks for the 2018 to 2023 competition season.For current year's competition tracks, go to https://iasca.com/sqc-tracks/.
iasca.square.site
I chose this since it's a bunch of high quality 16/44.1 kHz content. I chose Track 7 on the IASCA disc, which is Anvil of Crom from Telarc's Great Fantasy Album, a very percussive track. I have that disc somewhere as well, so I could check the liner notes, but this is DDD and done by Telarc, which was one of the best audiophile labels in the 90's. I chose this because I saw the imaging artifacts.
I then recorded:
1) Node Icon from network share --> E1DA Cosmos ADC at 24/96
2) Fosi ZD3 from USB --> E1DA Cosmos ADC at 24/96
Fosi ZD3
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Node Icon
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There is a huge shelf above 16 kHz which is sort of weird, since I see that on the original FLAC too. Notice the spurious tones at 30 kHz? That's the problem of the QRONO d2a.
So then, it's worth looking at the original source file:
Source File
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That's my fault. There isn't a lot of content above 16 kHz to begin with.
So, you'd ASSUME that I chose a poor test track. And you'd assume that all of the content above 16 kHz is buried to -70 dB or lower, and be completely masked.
I then brought things into DeltaWave. Pretty obvious that white is the Fosi ZD3 and blue is the Node Icon.
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Nothing surprising yet.
But QRONO talks about phase, so I compared the Fosi ZD3 and Node Icon. So now we are seeing a difference.
Phase: Fosi ZD3 vs Node Icon
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This is interesting because the difference occurs in the audible range of 6kHz and up.
So now, the test is to compare the digital file at 16/44 versus the recordings...
Phase: Recording of Fosi ZD3 vs. Digital File
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Phase: Recording of Node Icon vs. Digital File
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Just before you come to your conclusion.... take a look at the Y-axis. Let's set them to be equal:
Bluesound Node Icon Recording vs. Digital File
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Fosi ZD3 Recording vs. Digital File
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So, with a test track that is capable of generating imaging artifacts in the ultrasonic range, if you were looking how close the recording of the DAC matches the digital file from the phase standpoint, the Bluesound Node Icon with QRONO d2a actually beats the Fosi ZD3.