#11
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AES E-Library » Is the AES/EBU/SPDIF Digital Audio Interface Flawed? This paper will let you understand why the SPDIF format is fundamentally flawed, and why such a things like clock linking are needed to overcome its problems. |
#12
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#13
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If you did, then I'm surprised you do not noticed fundamental differences between the two interfaces (asynchronous USB and SPDIF).
Yes, it all boils down to the way the clock is beeing sent and the subseqent clock recovery. And yes, it makes all the difference. High levels of jitter in SPDIF interfece are unavidable due to finite bandwitch of cables, which leads the distorted 'square' signal, which in turn makes the whole interface suspectible to noise, reflections inside the cable and most important 0V crossing point variations. If you find the Dunn/Hawksford paper to difficoult to follow (you can read it here: http://www.scalatech.co.uk/papers/aes93.pdf) than I recommend an article written by Dr. Remy Fourre for stereophile, which is much more accessible: http://www.stereophile.com/reference/1093jitter Last edited by Elberoth; 05-01-2012 at 02:55 PM. |
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#15
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Well, if you really think that both Dr. Fourre and Dr. Hawksford were wrong in those papers, then I suggest you write your own rewolutionary paper and publish it on the next AES convention ...
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I did not say their paper was wrong. That paper has been out there for 20 years. I challenged your premise that USB as a delivery tool was better than SPDIF. I do not see anything in their research comparing the two since USB was a non-factor at the time. The does, or a least seems to state, that if amplitude and timing are controlled, jitter should be out of the threshold of our hearing.
Jim |
#17
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OK, I misunderstood what you had in mind.
Anyway, asynchronous USB is a much better interface format than SPDIF, simply because with USB you put the DAC clock in charge, and it can be very clean and free running — no PLL — very low phase-noise. In SPDIF based playback solutions, you have to transmit the clock signal from the transport to the DAC, via the inherently jittery SPDIF interface and then synchronise the transport and the DAC clocks in a PLL loop inside the DAC, which adds even more jitter. This is why some companies (dCS, Esoteric, Wadia etc) introduced a separate clock signal cables - this solution allows them to overcome basic SPDIF limitation, by feeding back the clock signal from the DAC to the transport. With USB (and FireWire) that is not necessary. |
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Some news from Munich.
I have spoken today with Charles Kim from Aurender, and he gave me some important info. The top of the range Aurender W10 is almost ready. It will feature Dual AES and SPDIF outputs, USB audio out plus Wordclock input. The W10 will be compatible with any clock able to generate 44.1 and 48kHz Wordclock signals, but will come with the RS 232 able that will allow it to control dCS clocks (for sample rate change). The W10 was displayed in a A10 chassis, but it is to receive a different, even more upmarket chassis to reflect its $15k price tag (ough !). The USB only Aurender should be out in 6 months time. No price is set yet. They said I may cost the same as the A10 - which would be a pity. The USB only model will have a higher specs USB audio out than the one used in A10. |
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#20
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Any news on RAID1 versions in the model range ? |
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