Jitter, AIR and USB

[Hifi_swlon]

To my way of thinking, using the phrase "bits are bits" to characterise a point of view about this is misleading.  Surely no one is arguing that the bits are somehow changed depending on subtle things like single or even multiple re-clocking, are they?  If they were, that would be admitting that the engineering principles we rely on to run the world are somehow faulty and need extra help (especially for digitised audio) which seems to be nonsensical.  By virtue of the same engineering this would be easy to detect anyway - think CRCs used by Ethernet and USB, for example.

The more interesting part of the discussion to me, at least, is about how the reliably-delivered stream of bits gets converted to analog, and whether there is any way for that process to be upset by the "upstream" digital equipment, isn't it?  I think one can hold the view that the digital stuff "just works" - so the bits you put in are the bits you get out, no argument - but still agree that there are plenty of other factors that can cause noise, distortion, etc. in the conversion process, any of which could depend on what is connected upstream.

Another way of putting this is that although it's straightforward these days to deliver a stream of bits reliably from A to B at audio data rates, it's still non-trivial to design a low-distortion, high-resolution digital-to-analog converter.  It seems that the focus of attention for many is to keep the bad stuff out of the DAC.  That's got to be a good idea in principle, but how much effort one wants to put into it in practice is obviously a very personal decision: for some people that's the hobby in itself, for others it's a means to an end (listening to music), and for others it's just "utter nonsense" (to borrow your phrase).  Each to his own, as always!

I'm sure you'll all have seen this, but it's interesting that he echoes thumb5's thoughts - the bits are all there and always have been - it's the engineering behind the clocks, power supplies, etc etc that decide the final outcome on a device-level.

https://www.computeraudiophile.com/ca/ca...gies-r656/

Quoting a bit of the following discussion from Dominique Brulhart of Merging where he touches on this in abswer to a question:

2) Stricto-senso, the "quality" of the bits transfered by Ethernet, USB, Firewire, Thunderbolt or even AES or SPDIF is the exact same. Every bits reach the destination intact and in the proper sequence. If it weren't the case we wouldn't discuss about sound quality but about glitches, pops, scratches or bangs. So, on the transport aspect, all those technologies are equal (if we put aside latency, number of channels, resolution, which are quantity considerations and not quality considerations). However, the sending and receiving devices can be more or less accomodating to the technology involved by these transmissions, some are synchronous, some are asynchronous, some have more or less jitter, some are more of less precise, etc... and it is then down to the sending and receiving devices to be properly designed to accomodate with these constraints. In theory all those transmission mediums can sound equivalent if the hardware implementing them is properly designed. So in that sense Ethernet can have some advantages, like a better galvanic isolation, specially if using optical cables. Ravenna is a very precise, low jitter and low latency protocol, so meaning that it can have, in theory, advantages in the design of hardware communicating with it. But it's main advantage is definitely its flexibility. Quality is really down to the engineers not to the technology.