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DACs: USB vs. Coax. vs. Optical - Page 2

post #16 of 55
12/12/07 at 9:35pm
In any case, you must remember that the USB cable and connector was designed for transmission of computer related data, not a digital audio signal. Not saying that it's bad at passing digital audio, just saying that it was not designed with it solely in mind like coax and optical were.
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post #17 of 55
12/12/07 at 9:37pm
Quote:
Originally Posted by mchang View Post
Can you translate for the layperson? Do the above improvements of coaxial and optical equal a noticeably better sound over USB?

I just got the 0404 USB, and am using it through USB. I haven't noticed the delays Ross1 mentioned (but I haven't been looking/listening for it). Should I run out and get a mini-jack-to-optical cable?
mini jack to optical........? If your PC doesnt have an optical or coaxial out at the back then you are best off using the USB. It would entirely stupid to have your integrated soundcard convert to analog only to reconvert it to digital then convert back to analog with the 0404.....
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post #18 of 55
12/12/07 at 10:26pm
Quote:
Originally Posted by Dr. Strangelove View Post
In any case, you must remember that the USB cable and connector was designed for transmission of computer related data, not a digital audio signal. Not saying that it's bad at passing digital audio, just saying that it was not designed with it solely in mind like coax and optical were.
Sorry, I don't mean to be rude......but just what point are you trying to make?

Data is data, regardless of whether it is audio data, a spreadsheet, a web page, whatever. If the system transfers it without error and within the time constraints required for the downstream device to process it optimally, what difference could there be? Your hard drive doesn't know that FLAC or mp3 file is music and treat the bits more tenderly, does it?

Coaxial cable was around for decades, transmitting ultra high frequency analog signals before digital audio came along.....and most RCA plugs are not ooptimally designed for digital transmission. Back in the mid-70's, when LED's were first produced in commercial quantities, it didn't take long for systems to be developed that used LED's and fiber optics to transfer analog audio signals to avoid RFI/EMI in radio stations, for instance. Neither coax cable nor fiber optic were designed specifically for digital audio.
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post #19 of 55
12/12/07 at 10:28pm
Quote:
Originally Posted by Penchum View Post
I can think of no reason to go USB when you have the other two available, unless portability is a must.
What about the fact that the 0404 USB, as I note above, uses special drivers that avoid the problems with converting to/from and transmitting the signal via S/PDIF?
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post #20 of 55
12/12/07 at 10:39pm
Quote:
Originally Posted by sejarzo View Post
What about the fact that the 0404 USB, as I note above, uses special drivers that avoid the problems with converting to/from and transmitting the signal via S/PDIF?
Is there some kind of wide spread problem with this I haven't heard about? All of mine work great and I haven't conversed with anyone yet that has had a problem with theirs.
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post #21 of 55
12/12/07 at 11:07pm
sejarzo was trying to explain how E-MU's implementation of the USB receiver allows reclocking of the buffer probably resulting in very low jitter. There is nothing inherently wrong with using S/PDIF.
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post #22 of 55
12/12/07 at 11:17pm
Quote:
Originally Posted by sejarzo View Post
What about the fact that the 0404 USB, as I note above, uses special drivers that avoid the problems with converting to/from and transmitting the signal via S/PDIF?
I think its more to do with USB having other downfalls, in that is just has less bandwidth. As I said, it DOES mean there is a significant buffer time if you say pause for 5 minutes halfway through a TV show, movie, etc. I found it took a good 5 seconds for the audio to come back and then for the video to sync back up.
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post #23 of 55
12/13/07 at 12:05am
Quote:
Originally Posted by milkpowder View Post
sejarzo was trying to explain how E-MU's implementation of the USB receiver allows reclocking of the buffer probably resulting in very low jitter. There is nothing inherently wrong with using S/PDIF.
Ow! Ok. I'm glad. With my notebook, it was a life (noise) saver for sure!
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post #24 of 55
12/13/07 at 12:32am
Quote:
Originally Posted by Ross1 View Post
I think its more to do with USB having other downfalls, in that is just has less bandwidth. As I said, it DOES mean there is a significant buffer time if you say pause for 5 minutes halfway through a TV show, movie, etc. I found it took a good 5 seconds for the audio to come back and then for the video to sync back up.
I'd have to presume that's not a problem with USB per se, but an issue with the player app, drivers, and device interaction in your particular set-up. USB as a data transfer method certainly doesn't suffer from a lack of bandwidth at all. Remember, the USB Audio device standard is the one with a limited bandwidth at 16 bit/48 kHz. There are a lot of USB 2.0 "prosumer" recording interfaces out there that can handle multichannel 24 bit tracks at 96 kHz.

FWIW, that's what the 0404 USB was designed to be--not a consumer external soundcard. On top of that, most recordists seem to run an absolutely barebones hardware and OS configuration to ensure glitch-free recordings (to avoid the OS from doing "other stuff" on its own, so to speak.)

For me, running Foobar to listen to music--with the source files anywhere from 16/44.1 to 24/96, FLAC or WAV--on both an XP-based desktop and notebook, the 0404 USB works just fine.
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post #25 of 55
12/13/07 at 1:29am
Quote:
Originally Posted by sejarzo View Post
If the system transfers it without error and within the time constraints required for the downstream device to process it optimally, what difference could there be? Your hard drive doesn't know that FLAC or mp3 file is music and treat the bits more tenderly, does it?
I was not implying that the actual audio data is in some way more fallible than other forms of data. What I meant was that USB is prob more prone to noise and interference than a properly shielded coax and good RCA connector. I know that the digital signal is pretty resilient, and you could prob use USB with great results, but when your dealing with audiophile applications, there is great effort put in to reject all forms of interference with the signal. All I was saying is that coax+RCA prob gives a cleaner signal vs USB.

Quote:
Originally Posted by sejarzo View Post
Neither coax cable nor fiber optic were designed specifically for digital audio.
There are versions of coax made specifically for digital audio, that's what I meant. Anyways, the fact that it's been around for a long time means it's prob a very perfected standard, were as USB has not been used for digital audio as long.


This is all based on my deduction and own readings, so it's not fact, just my opinion.
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post #26 of 55
12/13/07 at 6:17am
Quote:
Originally Posted by Dr. Strangelove View Post
I was not implying that the actual audio data is in some way more fallible than other forms of data. What I meant was that USB is prob more prone to noise and interference than a properly shielded coax and good RCA connector. I know that the digital signal is pretty resilient, and you could prob use USB with great results, but when your dealing with audiophile applications, there is great effort put in to reject all forms of interference with the signal. All I was saying is that coax+RCA prob gives a cleaner signal vs USB.



There are versions of coax made specifically for digital audio, that's what I meant. Anyways, the fact that it's been around for a long time means it's prob a very perfected standard, were as USB has not been used for digital audio as long.


This is all based on my deduction and own readings, so it's not fact, just my opinion.

No, that's a lot of nonsense. There is no noise in USB.


EK
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post #27 of 55
12/13/07 at 6:56am
^I doubt that, a quick google brings up quite a few results on the subject:
End USB Noise Without Stopping the Bus

Quote:
Originally Posted by Website
...Ideally, the magnetic flux produced by the differential signal currents has a cancellation effect and, for that reason, is not a large contributor of EMI noise. However, harmonic noise from IC drivers or peripheral circuits can radiate onto the signal lines and be transmitted through the USB cable, which can act like an antenna.
But then again I am no expert, care to explain your reasoning?
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post #28 of 55
12/13/07 at 7:21am
Quote:
Originally Posted by Dr. Strangelove View Post
But then again I am no expert, care to explain your reasoning?
Thousands of hours of listening time with various USB audio products.

I'm sure you could find some ultra-cheap $10 product and connect 10+ metres of unshielded USB cable from 1998 wrapped around a motherboard and power supply, and detect some noise that may be attributed to USB. Otherwise, no, USB is the best option.

If you have to worry about the cable between the transport and the DAC, then the DAC has failed it's primary purpose.


EK
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post #29 of 55
12/13/07 at 7:59am
Listening via ears is not the most scientific method of proving something of that sort, however, I agree it's negligible and irrelevant. The same prob goes for coax, and (To a degree) optical, in which case your ears prob won't be able to tell you which is the best way to route the signal.

Again, all I was saying is that if you want to be uber picky about it, coax is prob the best solution.
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post #30 of 55
12/13/07 at 8:46am
I trust my ears more than any whitepaper, specification sheet or measurements. Case in point --> coax is theoretically better than optical; but I always opt for optical.

To me it just sounds better; more organic. Placebo? Possible. Delusion? Probable.
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