Digital Audio Output Differences? Is USB Audio Really The Top-notch?

[preston8452]

Hello guys,

So after some struggles between spending time in optimizing my PC audio functionalities and adopting a dedicated music streamer, I opted for the second one.
I purchased the Munich M1T by Silent Angel, given it's good reviews in UK and Germany and Switzerland, I thought it wouldn't hurt to give it a shot, but frankly speaking, the mainly reason was because the price fits my wallet more hahahah...

Anyways, so there are several digital outputs on its back panel, AES/EBU; I2S(HDMI), Coaxial, USB Audio, hell hahah, I have literally no idea which one is better or which can provide a special feature or something, I mean it does show that the USB Audio supports up to up to PCM 768KHz and DSD 11.2M (DSD256), but does that the higher the sampling rate, the better the sound quality? I just can't make sure...

And if the USB Audio can provide the " best " digital sound quality, then why added other ports? Ain't that just costing more on the manufacturing end?
Hope you guys can give some insights on this, or share some of your experiences, because this is the first time I saw an AES/EBU port on a audio streamer...

Best,

[jophill]

The M1T looks like a good product to me. The right functions and a good price.

The choice of interface depends on what "best" means personally (I see your quotes). I am of the philosophy that in the digital parts of my system "best is digital done right". That philosophy leaves primarily loudspeaker choice to satisfy the "best is what pleases me" part of assembling a complete system; plus the list of things digital can do wrong so I can avoid them.

I think all the the interfaces you mention are perfectly good and to me the choice starts with the question about what interface the DAC supports; and what music data rates/formats are needed for the sources. All of the interfaces can carry digital data with accuracy (lack of data errors) that's essentially perfect as long as they are in good order.

My default choice today is USB as long as the DAC supports asynchronous USB (i.e. not synchronous or adaptive). That means the all-important clock in a digital audio system - the one that actually drives the D to A conversion - sits in the DAC isolated from the rest of the system. You can mess up a D/A conversion audibly if the data is perfect but clock used is not good enough (too much jitter). Although "good enough" may be a subject for debate in principle it's a solved problem these days.

The other interfaces derive the DAC clock from the incoming data stream. Architecturally wrong but actually OK since the industry started producing AES/SPDIF/TOSLINK receivers with excellent clock extraction performance (and I think it's the same for I2S but I have no practical experience). So USB is a personal preference but I would not object to any of the others as long as I could check on the receiver chip. But it's probably a safe bet these days to assume any non-boutique DAC will be perfectly good enough.

Of the others I would use SPDIF (coaxial) in preference to its technical cousins AES/EBU or TOSLINK (optical). I wouldn't expect differences but it's arguably a little simpler and I like simplicity as long as it works. I2S however is new to me so I have no comment (although I have read the standard).

On data rate my philosophy is that the best data rate is the one used by the source material. I prefer to keep data rate unchanged. Changing it does not add any information that wasn't present in the original audio. However, some people like to up-sample to as high a rate as possible so the influence of the audio filtering in the DAC is reduced and you perceive the audio filtering in the up-sampler instead. I have tried that but differences are too tiny (to me) and fade into insignificance compared to the major differences I perceive in source mastering quality. But YMMV.

Several interfaces? Bill of materials additional cost is small and you widen the range of customers whose DACs have a compatible interface so you probably get extra sales to more than compensate.

[Bulldog]

I use both the toslink and coaxial inputs on my RME DAC. I can't tell the difference on the same (CD quality) source material. I haven't tried the USB input yet - which I understand supports very high resolutions. It would be interesting to compare the results one day. At some point I'll try a high resolution music streaming service.

I agree with jophil; It's all about the quality of the source material. I'm not a big fan of up sampling.