Do HDMI cables make a difference for IIS/I2S/I²S-HDMI audiophile DACs?

It's taking a bit longer for my testing of the inexpensive I²S/IIS/I2S-HDMI DDC boxes due to some unexpected results which I'm chasing down currently; hopefully that gets resolved or understood soon.

In the meantime, let me address something that folks might be curious about related to this topic of the I2S-HDMI interface... Does the HDMI cable make a difference to the sound quality?

As with much of audiophilia wherein some members of the culture have the belief that "everything makes a difference", obviously this is not the case and I do not recommend this kind of mindset. There are many things that don't make much, if any difference (as discussed here and here) based on experience and understanding principles of the technology.

Since I have not seen measurements examining the effect of HDMI cables on I²S performance from a DAC, let's do some testing here.

Visit to a "more subjective" leaning friend. And something like Synergistic Research "Transducers" (HFT, GCT, ECT...) to try.

Hey everyone. I'm still waiting to finish the measurements and write-up of the USB DDC boxes discussed last time (a few things I need to double check on!). In the meantime, I thought I'd share some thoughts and pictures with you of a visit I made to a friend, Paul's, place. You'll see that he is much more of a "subjectivist" than I am.

Above, we see his listening room which is capable of multichannel playback as well for music and movies. He's a multichannel enthusiast who values the immersive experience and has a large library of surround content in PCM and DSD - great to see!

Clearly, Paul is a Linn fan with almost an all-Linn system. He has front Linn Akubarik Exakt (Katalyst) active speakers, an Akurate 225 center channel, and a pair of Akudoriks as rear/side channels. Over the years, he has been experimenting with Linn Space Optimisation and wrote an article about his experiences (he contacted me after he saw my tests with Linn SO last year).

Inexpensive USB2.0 Digital-to-Digital Converters (DDC) Pt.1: Douk Audio U2 PRO (Upgrade Version) and SMSL PO100 PRO - initial look, about I²S-HDMI. In praise of unofficial Atmos mixes!

This SMSL unit also does MQA decoding for those who want the feature. Unlike the Douk, this box only has an LED to indicate MQA decoding status but does not tell us the PCM or DSD samplerate.

While I've tested some inexpensive devices (like the Topping D10s DAC) which have the ability to convert USB 2.0 input into S/PDIF output, I have not specifically looked into these Digital-to-Digital Converter boxes which some audiophile reviewers (like this fellow, and this) seem to rave about.

For me, there just hasn't been any reason to be particularly interested since other than conversion from one interface type to another, the other promise of such devices - the reclocking capability - just hasn't been of great interest to me. As far as I can tell from listening, it's not like jitter has ever really been much of an issue unless severely bad for any decent modern device I've ever come across even at low price points (nor was jitter really an issue even with old CD players)!

However, since I have not tested I²S/I2S/IIS, I figure I'd buy both the Douk Audio U2 PRO 2025 upgrade version (US$63; Amazon Canada) and SMSL PO100 PRO (US$74; Amazon Canada) boxes to try out; have a listen and run some measurements. Unfortunately due to time limits, I'm not quite ready to show the measurements yet, so keep an eye out for those results, perhaps next week! For now let's just introduce you to these devices and talk about the I²S-HDMI connection.

As typical of the majority of my reviews/critiques, I bought these through retail channels.