TiredLegs;395965 Wrote: > Sean, > > Thanks for the explanation to someone (me) who doesn't know what he's > talking about when it comes to the inner workings of these devices. It > just seems bizarre to me that the bulk of this thread discussion is > about handling extremely minute variations in the timing of data > delivery for less than a gigabyte of audio data that represents about > an hour of music, when computers move gigabytes of data around in a few > seconds without a problem. It is conceivable that a word clock scheme > will ever make it into mass market audio gear?
If you're willing to overlook clock noise then the unidirectional, single conductor that comprises s/pdif is really quite elegant, and makes it both easy to use and inexpensive to implement. You will never see word clock connections on mass market equipment because it requires manufacturers to provide additional connectors, and users to connect another cable to them. This has not only cost implications but significant real estate requirements on the crowded back panel of an a/v receiver. Besides, if you are connecting a standalone DAC and care about jitter, then you are already miles outside the mass market for audio gear. However, as we move away from media which are designed to be read in real-time (CDs, DVDs) and towards home networks, internet streaming, etc you will see the issue disappear on its own, as the clocking inevitably moves towards the DAC in these schemes anyway. But even then, consider that A/V receivers in their present form (basically they are just "input selectors") would have to be completely rethought, because that functionality has no place in a fully networked scheme. There is a lot of legacy behind the design that s/pdif delivers in real-time. Even CDs were designed more like LPs than hard drive platters, in that their tracks are laid out in a spiral to allow the laser to track them continually from start to finish. There is a deeply ingrained way of thinking about information transfer that it necessarily occurs at whatever rate it's being consumed (technically the term for this is "isochronous"), and only with recent, powerful PCs, cheap packet networking, hard drive storage etc can those assumptions finally be let go. But it will still be the case indefinitely for other technologies such as broadcast/satellite delivery where you have a unidirectional, one-to-many transmit path with no possibility of doing flow control. In the video world the possibility of internet delivery replacing broadcast has been "just around the corner" for a long time - it will happen (eg AT&T U-verse, Apple TV, etc) and maybe soon enough we'll just have ethernet plugs in the backs of our TVs instead of the ridiculous HDMI interface. Anyway the point is, the designers of s/pdif didn't deliberately choose a "sub optimal" scheme. Maybe they were unaware of the problem of jitter (I could believe that actually) but just as easily they could have considered it and made a decision that it was outweighed by the cost and usability advantages of using a single conductor. We are getting to the root of why high-end audio is such a special niche. -- seanadams ------------------------------------------------------------------------ seanadams's Profile: http://forums.slimdevices.com/member.php?userid=3 View this thread: http://forums.slimdevices.com/showthread.php?t=50147 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
