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Did We Overhype USB Audio And Overlook Possible Pitfalls?


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Hi Guys - The title of this thread "Did We Overhype USB Audio And Overlook Possible Pitfalls?" is meant to be read as a question, not a conclusion or suggestion.

 

 

A little background:

 

Remember the days of adaptive USB audio and 29/96 limitations? I remember thinking how great this was considering we could then play high resolution rather than being stuck at 48 kHz and lower. Then I remember the wonderful introduction of asynchronous USB and even higher resolution playback up through 24/192. Wow, life was good, especially when compared to where we had previously been with USB audio. Then came DSD via DoP. Another neat step in the USB audio evolution. More recently we are in a sample rate arms race of DSD256/DSD512 and PCM 32/384 or higher. I'm not suggesting this arms race it's beneficial, especially when so many members of the CA community really enjoy sample rate and format conversion prior to sending the audio to their DACs. But, in this evolution to higher and higher rates, it seems like very few people and still fewer manufacturers are talking about other areas of USB audio improvement. Companies like AudioQuest (Jitterbug) and UpTone Audio (Regen) have developed products to improve the USB audio experience. Many people will never go back to listening without one of these devices. Also, some manufacturers refuse to put USB inputs on their components (Berkeley Audio Design) while others recommend using digital inputs other than USB (Schiit, Hegel).

 

 

I've been thinking long and hard about USB audio for several months and even talked to some well respected audio engineers about the topic. I've been listening to many DACs using different inputs and trying to judge whether I can conclude anything with respect to the quality of an input and have this judgement be relevant for anything other than the exact system I'm using at the time. I haven't been able to come to any conclusion stating that one input method is always better than another or than USB is inferior to Ethernet or AES etc... But, I have listened to DACs in my system that certainly sound worse via their USB inputs. I raised this finding with a few engineers in the industry and was surprised to hear them either agree with me, take it a step further and says USB is too flawed, or provide me with solid objective information for using USB in other ways. One example of this came when talking to a manufacturer who has offered USB inputs on its DACs for many years and now offers Ethernet inputs (in addition to USB). This manufacture thinks Ethernet is capable of much better audio than USB. Sure that's one manufacturer's opinion and not indicative of anything else, but it's someone whose opinion I highly respect. Another manufacturer I talked to at CES told me something very interesting about his tests with USB inputs. He said when he physically removes the USB input / receiver board from the DAC and places it on top of the chassis for testing, the DAC measures better. This physical separation of USB from the DAC was objectively a better solution. He also said his customers weren't interested in another box or different solution, so he was sticking to the current integrated USB design. He ideal solution would be to have a USB to AES converter to send AES into his DACs. This is exactly what Berkeley Audio Design has been saying since it released the Alpha USB years ago.

 

 

That said, I'd like to discuss the question of whether or not we (me included) overhyped USB and/or overlooked some of its pitfalls, in addition to other people's thoughts about anything USB audio related.

 

Again, I'm making not judgement or conclusion about USB audio and in no way suggest that people render an opinion based on my questions. It's simply a topic I'm interested in discussing and think we could all learn quite a bit from members of the CA community.

 

If anything is wrong with USB, it's the fact that the high-end audio industry seems to be stuck at USB 2.0. The problem is obviously not the interface itself which continues to evolve. Going to USB 3.1 (Superspeed) would solve a lot of problems, make interfaces more reliable, obviate the need for DAC specific asynchronous drivers (in Windows and class drivers on the Mac), and open the door for new Internet protocols such as MQA and the myriad of high-resolution formats that MQA will make available via USB, not to mention the possibility of streaming 24/192/384 and perhaps higher and DSD without any data compression of any kind.

George

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For whatever it's worth, I recall having a long talk at the Newport Beach Show (at least that's where I think it was) with Keith Johnson (of Spectral and Reference Recording fame). A very nice and very knowledgeable man.

 

And I asked him about which digital interface he preferred. He would not state a preference. He firmly believed that the quality of the interface was secondary to the quality of implementation of that interface in the respective device.

 

While I'm certainly not qualified to judge, his explanation had a ring of truth to me.

 

Joel

 

A lot of industry "personalities" are reluctant to endorse or condemn any current technology or protocol for fear of being misquoted or quoted out of context. Can't say as I blame them.

George

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Hi George,

earlier in this thread you said

 

 

 

I may be misinterpreting this, but it sounds like you are saying that audio drivers are not necessary for superspeed. You specifically mention class drivers which I interpreted as meaning generic audio class drivers. If this is what you meant then what is superspeed using other than audio class drivers?

 

John S.

 

 

Hi John:

 

You didn't misinterpret. I misspoke. I meant the Isochronous firmware such as Gordon Rankin's "Wavestream" product. Don't know what made me conflate that with the drivers except perhaps the fact that I had been up all night when I wrote that. USB 3.1 has isochronous operation as part of the spec. While USB 1.0 through 2.0 use a "speak-when-spoken-to" protocol requiring something akin to "Wavestream" on order for isochronous or device initiated communications towards the host, USB 3.0 and 3.1 was designed to allow this without having to add third-party protocols. Sorry for the confusion. I'll go stand in the corner with a dunce cap on my head now....

George

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The Dragonfly comes to mind.

 

 

Definitely! I also understand the latest Meridian Director with MQA is also very good and has the added advantage of being able to take an SPDIF input as well as USB and being a full 24/192 DAC. I haven't heard the MQA version (is it even out yet?) but I have heard the one without MQA, and I have to say Meridian's Apodizing filter makes this DAC sound excellent.

George

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