Computer based audio and I2S?

I just watched Pauls video this morning on I2S, and it occurred to me that this protocol, technology or what ever one likes to refer to it as might be worthless with a computer based music server vs a transport that by default outputs I2S if only for a few short inches or less. Audio files streaming via USB would not by default start out with an I2S protocol, so why then would someone connect to a bridge device such as the Matrix or SingXer SU-1?

Seems to be a wasted effort and step or is there something I am missing?


I think in this case there would still be a couple of benefits:

  1. The DAC wouldn’t need to decode the USB stream (hence more processing, hence slightly more noise)
  2. No 5v wire carrying noise
  3. Separate clock wires

I use a Matrix X-SPDIF connected to my laptop via USB and to my DS Dac via HDMI, and it does sound way better, for the reasons listed above, and also better isolation from the laptop, and less noisy digital signal.

  1. True
  2. The I2S connection to the DS Dac does impart a 5v potential (from the Dac side).
  3. The clock wires are unused (by the DS Dac).

Does the Matrix offer any form of isolation?

I’m not sure what you mean by less noisy digital signal -they are both likely bit perfect.

The Matrix has galvanic isolation between its inputs and outputs. “Bit Perfect” is sort of irrelevant here because we aren’t talking about the digital signal as much as noise contamination, which is very audible from most USB sources. I understand that Innous has very good USB outputs, but for less advanced digital sources the Matrix I2S makes a pretty noticeable difference.

At the moment, I’m without my Matrix and using a very spendy USB cable and iFi iPurifier 3, but missing the I2S. With I2S (and also Toslink) I find I can hear the full reverb tails on things that get obscured with USB.

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Yeah, I looked on the Matrix web site, but could not find any information about isolation, galvanic or otherwise -thank you for the information.

That’s why I said I didn’t know what you meant since in the context of a digital signal, better isolation and less noisy are the same thing.

I hope you get your Matrix back soon…

Thanks for the info guys. At the risk of being a devils advocate and also providing yet another solution to the issues you are discussing consider the ITona USB Isolator (link below) which I do use in my set up. Before we go to much further I should also mention I do not currently own the DS DAC, but have the Holo Spring DAC also available at the link below.

From my perspective it would appear while using any of these bridge devices we take a USB signal where clocking and data are all one one leg, then convert that signal again to separate clocks and data via I2S, and then once again back to a normal audio file where clock and data are once again on the same wire. Worse still from what I have read error correct does not or cannot occur with an I2S protocol.

Regardless I would encourage anyone to consider using one of these devices. From my perspective with or without a bridge device the difference with USB only transmission is quite profound and potent. The link provides quite a bit of technical data and scientific proof of these devices.

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I was very reluctant to try the Matrix because of the cost and difficult return policy. I tried multiple USB cables ending up with the Audioquest carbon at $150 which was the best price/performance that I could find at the max I was willing to spend on a usb cable. Then moved to a bridge ii with Audirvana and found greater improvements. Then finally moved to audirvana + Matrix. I struggle to understand why, but it sounds better than all of the prior solutions that I mentioned above.


Such is the magic of the Matrix.

Night-and-day difference in my system.


I switched from the Intona to the Matrix which I found much better. I’m using the i2s out to the DS Sr.


In a PC based system it’s not an absolute necessity to output USB, especially if you have a spare PCIe slot.

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Just curious why did you not use the Intona in conjunction with the Matrix? This is what I do thus far with the Singxer SU-1. Regardless I guess I should look at the Matrix again assuming it works with the Holo Spring DAC.


Well I did try it but preferred things without the Intona, plus didn’t want to deal with that many boxes/connections. The Matrix makes the Intona rather redundant IMO.

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Modern high end PC’s have audio out over HDMI from the video card. this is listed in Device manager under “sound cards”. Is this I2S? You could just run a very good HDMI cable right to the DAC if it is! You would not need the Matrix. The Matrix may be and is indeed great but so is not adding stuff to your signal chain! I am not sure if our DAC’s will accept this “signal” or not. For one thing I am not sure if it is already decoded to analog by the DAC on the video card. There must be some way someone can make this work with just an HDMI cable! Someone please figure this out! I have a very good feeling just whom could if he is up to it :slight_smile: Although I am sure there are other capable coders as well, notwithstanding myself. We want to grab the signal “before” it is decoded by the DAC on the video card and we are all set here! I do not know about ATI but I can work with Nvidia. There drivers are C++ in a VB container. Of course I could not, nor will I legally release backwards engineered drivers without their express written permission. If that were to even happen it could take months/years for their approval process anyhow. So, hopefully there is a simpler way anyone knows of. Put your money in a good HDMI cable then.

It’s not, don’t do it, damage may ensue.
I2S is meant as an internal comms protocol, but some high-end manufacturers have chosen to use it externally (with good reasons of course) but there is no standard cable / plug for I2S, so some use HDMI cables (a good choice, apart from this confusion) and some use ethernet-style connectors (and those are NOT ethernet so also confusion).
This is a hardware thing, a different PC driver will not fix it.

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I believe an I2S PCI-E card is available though - “Pink Faun” I believe?


It certainly is, but its output resolution is rather low - limited to 192KHz. I would pass.


It should be point out though PCI-E cards will only work with desktop workstations. Laptops and computers like Mac Mini’s would be out of luck with this type of scenario. Regardless I am a bit reticent to believe any computer regardless of what cards are installed “natively” have the ability to send audio files out in the I2S protocol. I’m not an expert on this but my guess is there is a conversion taking place to I2S.


I transport DSD 128 packed in 192 kHz DoP over USB. I don’t know if I would hear a difference between any high res file beyond 24 or 32 bit and 96 kHz or beyond DSD 64. With the DAC in the Stellar I have a hard time hearing a difference between red book CD and high res stuff to be honest. Lossy and lossless, I can distinguish when I listen real concentrated and switch between the same song in lossy and lossless. I buy Blue Coast Music as DSD because Blue Coast Music has excellent quality recordings (they know what they are doing, and they record in DSD, so I prefer the original. I have the impression DSD is less harsh, but it certainly does not sound worse than red ook CD’s I like it.

I also watched Paul’s I2S video very recently. I found it helpful after having read about the new AMD TRX40 chipset which might be giving birth to a conspiracy which I’m calling I2Sgate (Think Watergate and Ukraine-gate).

I’m trying to figure out what the bleep is wrong with AMD that they could not make I2S available via the chipset to integrated audio.

What motherboard vendors have decided to do, in the way of MacGyver, is to bridge a RealTek HD Audio codec to a RealTek USB audio bridge. I’m pretty sure this is not the best thing since sliced bread in regard to PC audio.

The response from purist audio card builders and audiophiles could be interesting. Check it out for yourselves to experience the astonishment… or dismay.

The AMD TRX40 Motherboard Overview: 12 New Motherboards Analyzed
"AMD did not include any onboard passth[r]ough audio in the chip[s]et. That means that all the motherboard vendors that are using a Realtek HD audio codec for the rear audio have had to include the ALC4050H audio codec to bridge the USB to the I2S. The Realtek ALC4050H is used to integrate a bridge between the chipset and USB 2.0 to give the Realtek ALC1220 all the necessary connectivity to the onboard audio…The TRX40 platform does not support the HD audio interface used on most desktop and mobile processors. "

TRX40 AORUS Master Vs. ASRock TRX40 Creator - Bigger is NOT Always Better.

I did get a response from Pink Faun when I inquired about TRX40 and their I2S PCIe Bridge. “We make use of the C-media CM8888 to generate the I2S signal directly from the PCI.”

The TRX40 integrated audio issue seems so bizarre to me that I’m wondering if it’s due to complacency on the part of RealTek or apathy on the part of AMD. I’m also wondering if some long-term contracts between motherboard manufacturers and RealTek are to blame. Maybe a revised chipset will appear after the holiday season.

Whatever happens, I think it could turn out to be an interesting story to follow. At the same time, I understand that it might not be as interesting to patrons of this site who seem more interested in generating quality audio outside of a PC rather than within it. I simply have not found another venue for discussing this. So, I hope you’ll allow some room for it here.

Additionally, most of my personal computers were build with AMD CPUs. If anyone could be considered an AMD fanboy, it would be myself. Yet, I’m not so enthralled and euphoric to refrain from being critical while others seem content to revel blissfully over AMD’s smack-down of Intel in the desktop space.

That does seem an omission, PC io chains in general seem often to be far from optimised - easier to chain together layers than design a new, shorter path…