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

@mike_in_nc 

Yes, that makes sense for computers.  My partner's Dell XPS 13 has so little space for any physical connections, it has an external adapter to support HDMI and Ethernet over USB!

What about separate streaming boxes.  What would be the best connection to a DAC for them?

Do most people stream via computers these days?  The only streaming I use is to check the music out before buying a disk, and I use WiFi (great Australian invention) to connect my mobile to the pre-processor for that.

The best connection is the one supported both by the streamer and by the DAC. Some manufacturers have their own connections (like Auralic’s Lightning Link) or use I2S, and many say that the sound is best if those are used. I have no experience with that.

Leaving aside specialty links, if USB is available, I like to use that, as it supports the widest range of sampling rates. Also, over USB, the DAC controls the clock entirely, without depending on the source. I will say, though, that with the new equipment I’ve tried recently, I cannot hear any difference between USB and SPDIF or AES3.

@richardbrand 

Why is it so?

You'll have to talk to the Accountants, then Marketing, Then the Lawyers who must grease the palms of the proper officials who will make sure they have  your complete cooperation with the proper authorities who will keep your competitors off your case should one arise.

USB is a terrible interface to a dac. Ethernet is better and i2s is even better. Most won’t know this because they buy cheap stuff and the cheaper stuff doesn’t include Ethernet or i2s. For a decade, all your high end manufacturers provided a proprietary link from their space player into their preamp or integrated or possibly a dac. They used hdmi/i2s for this. I use a streamer that doesn’t even include usb out, only i2s into my dac

It depends on the manufacturer in my experience. I have a Holo Audio Cyan 2 DAC.  It has multiple inputs.  Holo makes a Red streamer which connects through i2S which is tailored to connect between the two units.  I didn’t like the Red and the apps I needed to use.  I went with a Innuos Zen Mk3 streamer instead which only connects using USB.  It sounds excellent in my system.  Would i2S sound better- possibly if I could even tell the difference with my old guy ears.  I love the Sense app that Innuos uses, even better than the BluOs app which was my previous favorite.  I only use HDMI connections with my TVs.  So many connections and so many different cables.   Pick what sounds good to you in your system.