Did We Overhype USB Audio And Overlook Possible Pitfalls?

[Jud]

Optical or wireless transmission have the inherent advantage of electrical isolation. I wonder if as much time and as many resources were placed into developing either of these, whether they would be ahead of where USB is now?

 

Isolation from the transmitter, yes. But even with USB this may not be the main problem. A bigger problem may be the electrical activity of the receiver on the DAC's PCB.

[Jud]

No one makes a DAC without a buffer. No this doesn't make a DAC immune to jitter, even theoretically, though it does prevent gross errors that would occur if the DAC ran out of data in the middle of a track.

[Jud]

So would feeding a DAC via coax input from a USB to coax converter be a better path (all else being equal)?

 

For me personally, it was not, and neither was USB -> Toslink or coax -> Toslink (by a long shot). For some folks a converter sounds better; for me and others, USB has been the best so far.

 

All anecdotal (on my part anyway), so up to you how much credit to give it.

[Jud]

However data integrity is not supported as the connection is unidirectional and there is no possibility for the DAC to tell the sender to retransmit if there is a CRC error on a packet. This is why some USB cables provide better SQ than others as the error rate is lower or zero.

 

I would be reluctant to ascribe SQ differences so specifically to this without actual information of the type goldsdad describes. I believe that I hear SQ differences between cables without ever hearing signs of more egregious errors (e.g., dropouts) even from what I consider the worst sounding cables. If I'm correct that I hear differences, and you're correct it's due to error rates, why would I never hear any indication of error rates high enough to cause dropouts even where sound quality is bad?

[Jud]

cool.

 

still (occasionally) fire up a 27” 2009 core 2 duo 3gHz imac running osx lion for work on legacy fcp7 files.

 

but, only late-2013 (or newer) mbps and mac pros do 24/192 output via optical/toslink. imacs = mid-2014 onwards, minis late-2014 onwards.

 

pre-2013 apple machines were/are limited to 24/96 (or lower) via optical/toslink.

 

...which illustrates a reason for USB ubiquity. Output any resolution you like, including DSD, from your chosen software or a downloaded file using a Mac laptop or mini you already own. Nothing else allows you to do this with less fuss and learning than a USB connection between computer and DAC. Spending some extra money on cables or boxen between the computer and DAC is less daunting for many (most?) than spending rare leisure time figuring out optical Ethernet or SDIF-1 on purpose-built servers.

[Jud]

Chris, getting back to original post. I would say that we did not overhype USB audio and overlook possible pitfalls at least compared to computer audio with AES/EBU output and i2s output. I started out making computer audio based servers with the Lynx Studio audio card for AES/EBU output. I also made a version with a Julia card that output LVDS i2s. From the server point of view we were able to tweak the sound at the hardware level and software level the same we do with USB and in some cases with the same parts. We could even tweak the audio signal external to the devices with a re-clocker. These designs would also fall under the knife as the sample rate wars moved the high bar. The implementation issues on both the server and the DAC is not new. The interconnects maxing a difference issue is not new. The power supply issue is not new. To me these are the same old issues in a different format.

 

Jesus R

 

Yes, I strongly considered Lynx or RME cards when first getting into computer audio. Bought a Julia, beautifully made card, but eventually sold it because FreeBSD lacked drivers for it.

 

As you point out, each type of device/interconnection/format has advantages and disadvantages, and it's how the individual implementation resolves these that determines sound quality.

[Jud]

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[Jud]

Hi Mani,

 

Most high end companies use marketing language to describe "technical" aspects of their products, as they do not believe the average audiophile is technically oriented enough to understand (the graph you have posted). While technically oriented audiophiles such as yourself may find this approach annoying (and admittedly I often do as well) it is common practice in the industry, and does not necessarily indicate any attempt to obfuscate the actual truth.

 

I think to a certain extent there is a bit of deliberate obfuscation, not to hide things from purchasers, but so as not to provide a "roadmap" to knowledgeable competitors. This has been a form of art in writing patents and patent applications, for instance, literally for centuries.