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

I am a bit confused about the frequent mention of USB in the context of stand-alone Digital to Analog Converters (DAC).  Why is HDMI left out?  Is this a US versus Europe / Asia thing?

The Universal Serial Bus (USB) was introduced in 1996 by a group of computer manufacturers primarily to support plug-and-play for peripherals like keyboards and printers.  It has only two signal wires, plus two wires that can supply DC power.

The High-Definition Multimedia Interface (HDMI) was specifically designed by a group of television manufacturers for transmitting digital audio and video in many formats.  It hit the shops around 2004.  There are 19 pins supporting four shielded twisted pairs, and seven other wires (3 of which can instead form a shielded twisted pair for Ethernet).

I have three universal disk players from Sony, Panasonic and Reavon, which all have two HDMI outputs, one can be dedicated to audio only, the other carries video or video plus audio.  (Only the Panasonic does not support SACD).  My Marantz AV 8802 pre-processor has 11 HDMI connections and only two USBs.

Of course, both USB and HDMI continue to evolve.  Then there is the Media-Oriented System Transport (MOST) bus designed by the automotive industry, which looks even better.

Why is it so?

128x128richardbrand
skeptikal's avatar
skeptikal
33 posts
 

@rbstehno 

How do you figure?  USB is almost always bit-perfect.  When it's not, due to something being horribly wrong, you would definitely hear clicks and pops.  High end USB cables are snake oil, and there is nothing wrong with USB in general.

rbstehno
1,454 posts
 

I don’t reply to cable naysayers, if you can’t hear a difference between cables, no sense talking anything audio to you.

pureclarity
72 posts
 

I used to stream from my Mac mini using the headphone out into an adapter for optical. But your limited to 96khz 24 bit. With an external streamer/dac like auralic, you can stream much higher resolution with less noise from a computer. 192khz/24bit and 512 dsd. No usb connection, all Ethernet for streaming or wireless and balanced output.

philgo01
73 posts
 

My take: Audio Video HDMI is only available within the video world.  BluRay players that can play SACDs works only with Home Theater receivers that can decode DSD. I only have experience with SAME BRANDED BluRay and HT Receivers. Not sure how well it works with mixing brands.

To make it more confusing, then there are SACD players that use HDMI (that is I2S, but uses HDMI cables, no video involved) that can be connected to external DSD capable DAC using I2S via HDMI cable.  It can be a bit complicated as I2S pin outs are NOT standardized. So caveat emptor

2psyop's avatar
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2psyop
1,598 posts
 

I2S was designed for audio. Toslink was a cheap way to send digital signals developed by Toshiba. USB was for data not audio. When you look at it from a cost and convenience factor and take into consideration what technology was available at the time, one can see higher end audio components are using I2S because it’s better engineering and better sound today. Of course anyone is free to use whatever connector that might have and if it sounds fine for them…. no worries. Paul McGowan of PS Audio explains these differences pretty well in his informative YouTube videos.

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