I have been using an RME ADI-2 Dac for some time using the usb input. Lately I have connected a Hegel hd2 which is more a soundcard than a Dac in between the computer and the RME Dac in order to connect via coax. This arrangement sounds better to me, would there be an technical explanation for this superior sound or could it just be my imagination?
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RME Dac set up
- Thread starter Bridges
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One way to retain your sanity: run a bit test when connected through the HD2 and when not. If they both pass reject the hypothesis that the HD2 is improving the sound quality.
See section 31.2 in the manual here: https://www.rme-audio.de/downloads/adi2dac_e.pdf
test files here: http://www.rme-audio.de/download/bit_test_wavs.zip
See section 31.2 in the manual here: https://www.rme-audio.de/downloads/adi2dac_e.pdf
test files here: http://www.rme-audio.de/download/bit_test_wavs.zip
HarmonicTHD
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The effect you are hearing are more likely due to non controlled listening tests and your (human) bias as opposed to any technical reason.
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Could very well be, but I was looking for a technical explanation, if there is one.
staticV3
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First, try the technical proof that Wicky provided.
If one configuration passes the bit test and the other fails, then we can think of more steps to diagnose the issue.
If both configs pass the test, then any effort would've been for naught as it's just expectation bias.
To run the test, you want to use an audio player with Wasapi Exclusive or ASIO and the player and OS set to 100% volume.
MaxwellsEq
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If the digital bitstream is being modified, you may hear a difference. You can check for this by passing a bitstream end-to-end and and ensuring it's bit perfect. If it is, then there is no technical reason for you hearing a difference.
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Thank you, I will try both. Is there also a possibility that by inserting the HD2, I have isolated the electrical noise associated with the usb port that so many engineers talk about?
staticV3
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The Hegel HD2 doesn't seem to have any noise isolating capabilities from what I can tell.
radix
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The HD2 has coax output, not fiber (toslink), so I doubt its breaking any ground loops or such.
What engineers are those? Don’t you mean marketing people? Do you hear noise from the RME via USB?
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radix
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How did you test? What source material did you use and how long did you listen to it each way?
Did you check that your computer is treating both the HD2 and RME the same? Are the software mixers for each set the same?
DVDdoug
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Noise is hum, hiss, or whine, in the background. You'd know if that was what you're hearing and you would have mentioned it.
Or, USB power tends to be noisy. Digital data is immune to it but occasionally, that noise gets into the analog-side of a USB-powered DAC, or audio interface. It's usually a high-pitch whine from the switching power supply and you can get it from a battery-powered laptop because the computer has switch-mode voltage regulators and there's lots of data-switching in a computer. It's not a problem if your DAC or interface has its own power supply, and it's mostly only a problem with microphone inputs on an interface where any noise gets amplified by the mic preamps.
radix mentioned fiber - Sometimes you get ground-loop hum with an electrical connection but with an optical connection you can break the shared ground and sometimes that will fix it.
As a rule, EVERYTHING digital is OK and you rarely get subtle problems/differences. My usual (but imperfect) analogy is that one flipped bit (a 1 switched to a zero or vice-versa) in your bank account is just a likely to cause a 1-cent error or a billion dollar error. Usually when digital audio data gets corrupted the sound gets very bad, or you get no sound at all, or dropouts/gaps in the sound, or pure noise. Even resampling is normally audibly-transparent as long as you stay at "CD quality" or better.
If you can keep everything "bit perfect" you don't have to give a 2nd thought to the digital-side of things. A lot of people strive for that. But sometimes you might want digital volume control, or EQ. or maybe you need a different format, or you want to compress to MP3 to get a smaller file, etc. And to keep things in perspective, the whole process of audio production is not "bit perfect". They are mixing, adjusting the levels, applying effects, and usually rendering to multiple different formats.
I'd recommending reading the 1st post here - Message to audiophiles... (I haven't read the whole discussion. The 1st post makes the point.)
And Audiophoolery
And What is a blind ABX test?
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