USB cable supposedly improving DAC sound quality? How can I take other posts seriously after that?
Dec 20, 2017 at 12:54 PM Post #301 of 431
I always enjoy it when someone trots out the "even my wife notices a difference" stories! We should start a drinking game based on that like the Bob Newhart game. Every time an "even my wife" turns up, we have to drink a beer. Every time someone says "I can hear it clearly, if you can't it must either be your equipment or your ears." we have to take a swig.

You truly are a bigshot I see, but that's ok as I am old enough with enough life experiences to know that there are asshats everywhere. I was only giving an actual event from a personal experience. Normally I would not mention it because it takes me talking her through it for her to "think" she hears something, she volunteered this all on her own this time. Even though I have professionally taught over 1000 people how to critically listen I still get excited when the light bulb goes off. All good though people like you provide my internet entertainment.

I use a $500 Mac Mini as my media server. If flawlessly puts out high fidelity stereo, multichannel and even HD video
LOL

Of course my short time here I have learned to take what comes out of your keyboard with a grain of salt. You probably even think your HP rig is better than a full on room setup. And if it is your doing something wrong.:beerchug:
 
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Dec 20, 2017 at 12:58 PM Post #302 of 431
Do you really think everyone is using a computer that was designed optimally for being used for high fidelity audio? That is certainly not the norm.
You don't need a computer that is designed for audio. You just need a DAC whose designer knows USB signal is not clean. Fortunately every designer knows this and most of them do a very good of isolating the DAC (chip) from USB noise (power and signal).

Here is some data to demonstrate that. S/PDIF interface (i.e. "audio" interface) versus USB:

index.php


If the computer bleeds noise, how come the USB input to the DAC works so much better than its S/PDIF input?

The above DAC costs only $129 so it doesn't cost much at all to eliminate the impact of the computer.

I tested two other DACs with similar results (USB being better than S/PDIF).
 
Dec 20, 2017 at 1:38 PM Post #303 of 431
You don't need a computer that is designed for audio. You just need a DAC whose designer knows USB signal is not clean. Fortunately every designer knows this and most of them do a very good of isolating the DAC (chip) from USB noise (power and signal).

Here is some data to demonstrate that. S/PDIF interface (i.e. "audio" interface) versus USB:

index.php



What is being measured here?
 
Dec 20, 2017 at 1:43 PM Post #304 of 431
We love anecdotal stories about "night and day" differences that "even my wife can hear" here. Welcome to Sound Science. Feel free to cheerfully ignore everything you hear.

By the way, what is an "HP rig" and what is a "room setup"?
 
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Dec 20, 2017 at 1:47 PM Post #305 of 431
What is being measured here?
Happy to explain :).

Roon media player is playing a "J-Test" (Jitter Test) signal at 24-bits/48 Khz. J-Test (at this sampling rate) is a 12 Khz tone with the rightmost bit toggling at certain frequency. That toggling causes cable induced jitter to exaggerate on S/PDIF. Ignoring that complexity, imagine this just being a 12 Khz tone. That digital data is then fed to the DAC two different ways 1) through a USB to S/PDIF bridge or 2) through the USB interface directly on the DAC. I then measure the *analog* output of the DAC by digitizing it, and performing a spectrum analysis of it. In other words, we are measuring the analog output of the DAC and seeing what difference there is between two different digital inputs on the DAC.

In an ideal system we would get a single narrow spike at 12 Khz and nothing else. Anything else is unwanted noise, jitter, distortion, etc.

What we see in my measurement is that using USB results in the noise floor going much lower than using S/PDIF interface. I am using generic USB cables and my everyday laptop as the source. The testing shows that not only is the DAC insensitive to any noise on USB cable or the source, but manages to produce better performance. So there is no noise worry here, either in the source computer or the cable.
 
Dec 20, 2017 at 2:05 PM Post #306 of 431
As a Chinese person who spent most of the time on the other side “Erji.net” and have seen discussions on Erji on this very similar topic extensively, I think one important theory and aspect hasn’t been discussed in this thread yet is to really look at the placebo effect and the psychological state when using more expensive cables.

Hypothesis #1: People hear different sounds or have different perception of the same sound at different time during the day or different energy level during the day.

Hypothesis #2: Your neural and body reactions to all sort of stimulus constantly changes. Basically your body at this moment will be different from your body at the next moment.

Hypothesis #3: when listening to more expensive gears in general, the listener will tune their mental state to heighten the perception of sound and also lead him or herself to pay more attention to the sound.

If any of the above hypothesis is true, then listening to ANY cable at different time could sound different to the listener. And the price effect will make the “different” become “better”.

Now. If using experience gears help the owner heighten their senses subjectively, and get them to appreciate what they have more, it might as well worth it to buy expensive cables. All the sound we hear is nothing but an image stitched together by our brain and conciousness. The upgrade of cable in this case is an updgrade of a more careful listening mindset internally. It’s the same effect when you look at the same painting on your computer or a painted wall in an office building VS in a museum or gallery - the content is the same but your mental state of accepting those content are different.

The setup of cable dac and amp is undeniably a highly ritual process and all eventually leads to some sort of respect to the music and the eventual focus is the music.

I want to propose that from this point of discussion moving forward, we can at least separate the objective measurement and the subject perception when it comes to “does it make any difference”.
 
Dec 20, 2017 at 2:14 PM Post #307 of 431
Maybe the best option is to ask for expensive cables for Christmas and your wife dummies up some cheap cables to look fancy. That was you aren’t put a lot of money and you get full placebo effect!

SeeHear, the short answer to your question is “Nothing you’ll ever hear.”
 
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Dec 20, 2017 at 3:01 PM Post #309 of 431
I know. If we aren’t having fun here, we’re doing it wrong!
 
Dec 20, 2017 at 3:54 PM Post #310 of 431
Happy to explain :).

...That digital data is then fed to the DAC two different ways 1) through a USB to S/PDIF bridge or 2) through the USB interface directly on the DAC. I then measure the *analog* output of the DAC by digitizing it, and performing a spectrum analysis of it. In other words, we are measuring the analog output of the DAC and seeing what difference there is between two different digital inputs on the DAC.

What we see in my measurement is that using USB results in the noise floor going much lower than using S/PDIF interface...

Thanks for the explanation.

However, aren't we really seeing the noise floor of the USB to S/PDiF interface? I'm not confident it's fair to extrapolate from there that USB is inherently quieter than coaxial. I'm certainly not sure that, in general, USB is even equal to the performance of my sound card via coax to any of my DACs. The noise floor measurement notwithstanding (either number is beyond perception, especially with a signal present), I have found USB to, at best, equal coax in a particular system. I've never heard it outperform coax in any system where a comparison was possible.
And, no, I'm not bagging on USB; I've heard excellent sound via USB in many systems.
 
Dec 20, 2017 at 4:16 PM Post #312 of 431
Thanks for the explanation.

However, aren't we really seeing the noise floor of the USB to S/PDiF interface? I'm not confident it's fair to extrapolate from there that USB is inherently quieter than coaxial. I'm certainly not sure that, in general, USB is even equal to the performance of my sound card via coax to any of my DACs. The noise floor measurement notwithstanding (either number is beyond perception, especially with a signal present), I have found USB to, at best, equal coax in a particular system. I've never heard it outperform coax in any system where a comparison was possible.
And, no, I'm not bagging on USB; I've heard excellent sound via USB in many systems.

Further those results are only on HIS system. There are far too many variables, different DACS, different USB transceiver cards, etc. to come to any worthwhile conclusions with those results.
 
Dec 20, 2017 at 4:23 PM Post #313 of 431
I tried 2 Good USB cables on my AR-XA just now. No sound at all? Need to hear this Cactus LP I found at lunch.

You are doing it wrong. Instructions for LP digitization:

1) Tie the USB cable in a knot firmly to the axle of the record player (this will keep it in place)

2) Tie the USB connector to the head of the vinyl player firmly, at a 90 degree angle pointing down for the highest accuracy read.

3) Run the vinyl player at max rpm (this ensure the least amount of jitter, due to digital's impatience with analog formats)

That's all. Finito.
 
Dec 20, 2017 at 4:45 PM Post #314 of 431
ferrets i just thought they were cute fur balls but wrap them around usb helps supposedly
 
Dec 20, 2017 at 11:12 PM Post #315 of 431
Further those results are only on HIS system. There are far too many variables, different DACS, different USB transceiver cards, etc. to come to any worthwhile conclusions with those results.
I tested six different DACs that have S/PDIF and USB inputs with similar outcome: https://audiosciencereview.com/forum/index.php?threads/battle-of-s-pdif-vs-usb-which-is-better.1943/

While nothing is 100%, this is pile more data than just the statement that PC generates noise on USB and cables somehow remedy that.
 

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