Why does USB feature so much in discussions about DACs when the newer HDMI seems better?

@devinplombier I am equally staggered! 

You did not mention the latest incarnation of USB which has a connection count of 24 wires!  The connection topography is shared with several other technologies including Thunderbolt!

The naming and description of this latest USB evolution (revolution?) is confusing in the extreme.

My understanding is that for use of the latest features, the cable itself needs to be active.  That is, it has to have embedded logic chips.  That's how it can carry HDMI, which itself can carry Ethernet.

@mikhailark Absolutely spot on!  On another forum, an audiophile claimed there could be no difference audible between CAT5 and CAT6 Ethernet cabling, because audio frequencies are much lower than Ethernet transmission rates.  Anyone who does not get the point, does not understand how audio is carried over packet switched networks.

By the way, Ethernet on its own does not guarantee that a packet will actually be delivered, nor does it guarantee how long it may take to transmit a packet.  To probe why, take a trip to the Hawaiian Islands and try to understand the ALOHA radio data system which was the genesis of Ethernet.  The secret is in the CSMA/CD acronym - Carrier Sense, Multiple Access / Collision Detection.

The internet is also packet switched technology, which is evolving mainly through Requests For Comment!  Audio over IP (Internet Protocol) uses packetisation, whatever the physical wire arranement.

SNS

You've nailed it perfectly. There are SO many reasons to use I2S if you can, and you explained it really well. I agree that short HDMI cables are best, but I've had excellent results with the Audioquest Vodka 48 8k/10k cable at 1 meter. For small budgets, the Supra 2.1 HDMI works really well as does the Audioquest Cinammon HDMI.....but those needed to be shorter than 1 meter for best results

It is true that there is no standard for I2S pinouts, but I've never had a problem with Supra or Audioquest. Also many DACS provide pinout configuration, I know that Denafrips does in all of their DACS.

The other benefits can be true of DDCs too, as it allows for: better quality clocks, galvanic isolation, optical isolation, separating the data and clock signals, and of course keeping the I2S signal in tact from the DDC through the DAC.....with no further conversion until the Digital to analog conversion in the DAC

@sns, @vthokie83

Good explanation of USB versus I2S, but nothing about the native audio capabilities of HDMI!  Remember, HDMI handles multiple audio channels at breathtaking rates and these days includes an Ethernet channel to boot.

I am starting to question why audiophiles don't advocate for mono over 2-channel stereo.  How many backward steps can be taken?

richardbrand

That's true, I did not....and I do understand your point. I'm not an electrical engineer (I'm mechanical) nor a builder of audiophile equipment. I was responding to the various USB/I2S/SPDIF/Toslink posts in between, and reflecting on my own personal experience with my system

@vthokie83 

No worries!  When I started this thread, I was mystified why USB was so prevalent when there is a purpose designed, point-to-point solution for high-bandwidth multi-channel audio in the form of HDMI, which is ubiquitous in modern TVs and Audio Visual gear.  I never expected anybody to mention 'legacy' formats like SPDIF or Toslink  and I had never even heard of I2S.  It seems that the inventor of extending I2S over cable is only interested in 2-channel audio.

I remember the fuss that arose over the introduction of 2-channel stereo when mono had been the only option.  It was going to practically double the cost of HiFi for goodness sake.  Now I am wondering if there is a similar reluctance to move to multi-channel audio, for a similar reason.  Multi-channel high-definition audio has been available on SACD for over 25 years now.

For what it is worth, I have an 8.1 system with no center channel.  The main front speakers are better quality than the rest!  Generally, the rear speakers carry ambient sounds from SACD but some recordings on Blu-ray have Atmos and use all my speakers for truly immersive sound.

Oh, that recommendation to keep HDMI cables short only applies when they are not carrying native HDMI signals!