USB DAC's quality limited by USB 1.1?
Dec 11, 2007 at 6:38 AM Thread Starter Post #1 of 17

whatisthematrixx

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After researching lots of DAC's and being interested in using USB rather than optical or coaxial, I can't seem to figure out why DAC manufacturers use USB 1.1 which is limited to 16 bit audio rather than USB 2.0 which could be 24 bit audio? I know the Apogee has the optional firewire input component, but I am not sure whether that is 16 bit or 24 bit.

Basically what I'm asking is whether using the USB 2.0 protocol would allow for higher quality audio and why manufacturers aren't using it in USB DAC's.

Thanks
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Dec 11, 2007 at 7:44 AM Post #2 of 17

infinitesymphony

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USB 1.1 can support up to 24-bit/96 kHz operation, AFAIK. This is how it's implemented on the Benchmark DAC1, which allows 24-bit/192 kHz via digital or coaxial S/PDIF input.

Some DACs use USB 2.0 to support up to 24-bit/192 kHz, such as the E-MU 0404 USB. I think that USB 1.1 is still commonly used for reasons of compatibility.
 
Dec 11, 2007 at 11:03 AM Post #3 of 17

EnOYiN

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I have never been aware that the bit-rate of audio content was related to the USB technology. For as far as I know this has nothing to do with USB but a lot more with the DAC and the implementation of it.

The speed of the USB 1.1 technology could be limiting, but only if the audio content would exceed the 12 Mbit/s.

Like infinitesymphony I too do believe that it most likely has to do with compatibility or maybe technological difficulties.
 
Dec 11, 2007 at 11:51 AM Post #4 of 17

tot

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USB has dedicated audio protocols with guaranteed bandwidth.

You can implement anything with USB, of course, but then you'll need special drivers for it, and whether it works depends what else is going on the bus.
 
Dec 11, 2007 at 2:33 PM Post #6 of 17

EnOYiN

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Quote:

Originally Posted by Tarkovsky /img/forum/go_quote.gif
EnOYiN enters the suburbs!
....

USB 1.1 has a latency advantage over usb 2.



And you are trying to say that...

?

Edit: I can't find anything on the latencies of USB. Do you have a link?
 
Dec 13, 2007 at 7:54 AM Post #7 of 17

whatisthematrixx

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hmm ok, I'm not too sure what the latency advantages are, but it's good to know USB 1.1 has dedicated audio protocols so that isn't the limiting factor
 
Dec 13, 2007 at 8:24 AM Post #8 of 17

EnOYiN

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Quote:

Originally Posted by whatisthematrixx /img/forum/go_quote.gif
hmm ok, I'm not too sure what the latency advantages are, but it's good to know USB 1.1 has dedicated audio protocols so that isn't the limiting factor


The advantage of a lower latency is only interesting for recording purposes and not for playback. If you've got a buffer size of 8000 ms it won't matter because you will just hear the music slightly later.

I would still love a link to some document in which I can see what latencies the various USB technologies have. Thanks in advance.
 
Dec 13, 2007 at 1:57 PM Post #9 of 17

regal

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The issue with USB DAC's is that the manufacturers want to use the PCM270x plus windows drivers. Only benchmark, M-audio, and uditriol (sp?) have supported 24/96. However I noticed that the new Citypulse is USB 2.0, maybe 24/96?
 
Dec 13, 2007 at 2:14 PM Post #10 of 17

infinitesymphony

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Don't forget about the E-MU 0404 USB.
biggrin.gif


I think that it might be the only USB DAC capable of 24-bit/192 kHz over USB.

Quote:

Originally Posted by 0404 Manual
USB 2.0 vs. USB 1.1 Operation (Windows only)

The 0404 can operate in USB 2.0 or USB 1.1 mode. 96 kHz and 192 kHz sample
rates are only available while operating in USB 2.0. The included E-MU USB audio Control panel software includes an indicator to let the user know which mode the device is running in.



 
Dec 13, 2007 at 2:50 PM Post #11 of 17

tjumper78

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Quote:

Originally Posted by infinitesymphony /img/forum/go_quote.gif
Don't forget about the E-MU 0404 USB.
biggrin.gif


I think that it might be the only USB DAC capable of 24-bit/192 kHz over USB.



SUPER Pro DAC 707 USB
 
Dec 13, 2007 at 3:31 PM Post #12 of 17

infinitesymphony

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Quote:

Originally Posted by tjumper78 /img/forum/go_quote.gif
SUPER Pro DAC 707 USB


The DAC chip in the Super Pro DAC707 is capable of 24-bit/192 kHz, but there are no claims that the DAC itself can achieve this rate.
 
Dec 13, 2007 at 4:07 PM Post #13 of 17

Tarkovsky

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Hello Enoyin. I was referring to the first level of commander keen 6 (I think it was that level)...
I read that info about usb 1.1 ages ago, it was explaining why a usb interfaces used 1.1 instead of USB 2, namely the mbox 2.
 
Dec 14, 2007 at 10:58 AM Post #14 of 17

EnOYiN

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Quote:

Originally Posted by Tarkovsky /img/forum/go_quote.gif
Hello Enoyin. I was referring to the first level of commander keen 6 (I think it was that level)...
I read that info about usb 1.1 ages ago, it was explaining why a usb interfaces used 1.1 instead of USB 2, namely the mbox 2.



Haha,

I never played keen 6 I am sorry. I stopped playing keen at keen 4. (the picture is of keen 4) Guess I will start Dosbox in the near future.
biggrin.gif


Either way. I'll try to find some info on it myself. There should be something out there which has some info on the latencies of USB.
 

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