If 24/192 is all it’s cracked up to be, surely you could hear the difference just by listening, no? 

I surely can hear the difference by using my headphones

The Sonos line in gets converted to digital, absolutely pointless exercise doing this. You may want to look at Amazon HD or Qobuz as these are supported on Sonos natively, 24/48 is all Sonos supports.

thx, but they are all limited to 24bit 48khz natively in the App. 

Of course you can.  So put it through the Line-In and tell us how it sounds. 

That’s all Sonos hardware supports, nothing more,

I can't hear any difference to streaming natively with Sonos App. That's why I raised this question.

Best Sound to my ears is streaming with Amazon Music Ultra HD via Sonos S2 App.

so it is about time that Sonos integrates Apple Music Hi Res natively, but I don't know if this will ever happen… (ALAC vs. FLAC)

It’s not up to Sonos, it’s up to Apple.  Sonos just supplies the API, and since there are other services offering HiRes, the API is quite capable of doing it. 

I understood that the Sonos Api is capable FLAC for Amazon Music Ultra HD, Tidal and Quobuz…

but the Sonos Api has to cover ALAC, so what is the todo for Apple? I don't think that Apple would change from ALAC to FLAC...

Sonos plays ALAC just fine, why would the API have to change?  The API isn’t playing the stream, the Sonos player is.  

So then I really don’t understand the issue what Apple has to do. Just deliver ALAC files to the API?

That's a question for Apple.

You may try Qobuz too, but you need to set at your Qobuz account with „external services“ the max samplerate for your Sonos system. There is a special Sonos setting.  So choose 48/24 for S2 for hires capable speakers. Tidal is only 44.1/16 via S2. Only Amazon Ultra (shows in S2 a small logo, when streaming in 24 or Qobuz are doing 48/24. With Qobuz: if source is not in 48/24 it falls back to 44.1/16 even when source is higher than 48. Using line in is NOT a good option when you can stream with 48/24, as line in will have that AD step. You do not have that conversion when you stream digital already. Streaming Qobuz via Roon and via Sonos connect (not Airplay!) should also work with 48/24. Tidal Master via Roon to Sonos did not check myself.

thx for all the replies!

I understood that it is useless to download and then convert a 24bit 192khz stream via DAC and send it to line in to sonos five, because the five is converting the analogue stream in something digital again. A lot of data traffic for nothing.

But does anyone know exactly what sonos five is doing when using the line in? it converts the incoming analogue stream in what exactly?

I understood that the line in is lower quality than 24 bit 48khz (which is possible via native Amazon Music Ultra HD what im using at the moment). I definitely can hear a difference by using line in with 24 48 (or 24 192) compared to native sonos stream 24 48.

The native stream sounds more precise and clear, the line in sounds warmer.

Yes, the AD conversion has a signature. Sometimes you even like that Puh, how the coversion at the Five actually works, I do not know. I am sorry. And just a tipp, I would not trust in anything you hear about this. This even includes statements from Sonos support. Too much bad experiences on such kind of questions please. However, from a practical point of view, what Sonos folks come up with technically makes sense imo. Their stuff simply sounds good! So myself decided, I do not care anymore about the technical specifics. And if I am really not happy with one of their products, which did never happen so far, I give it back. So, just go with what you like to listen most too. :)

one additional phenomenon I noticed:
I can play Amazon Music Ultra HD / HD in all my rooms except in the living room. There it shows no HD or Ultra HD sign in the Sonos App. There is a Sonos Beam Gen 1 in Surround Setup with 2 Play1 as Rears and a Sub installed.

Is it not possible to play Ultra HD in a Surround Setup?

Take a look on this an the listed speakers for 48/24. S2 does not automatically imply 48/24 capable. Old speakers are special, like Play 1 and even sub gen 1. If you really want to know about your old speakers for 48/24,  you may have to give Sonos a chat, that they can check you speakers. For old speakers it depends even on the build date and not only the model. So, Play1 and even Sub coluld be critical. https://blog.sonos.com/en-us/hi-res-audio-guide

thx!

I can confirm that play1 is not able to play 48/24, but HD (41/16) is possible.

I have also some Symfonisk table lamps (gen1) and they cannot play any HD or Ultra HD format. On the link it is listed that it should be able to play 48/24. Anyone some info about that?

It’s tricky to make any comparisons between the various quality levels delivered by the streaming services. The “HD” version offered by the service might originate from a different master and will almost always skip the compressor. These versions can sound distinctly different, regardless of how they are played.

Even in the days of CD’s and LP’s there were differences between releases. In some cases it was difficult to accept that all of the releases spawned from the same studio session.

I can definitely tell by listening that the line in does not pass on the hi res audio signal, it digitizes it to something far less than what the artist intended.

Any line only takes analog signal voltages; none can take or directly pass on a hi res digital input. And how exactly do you know what the artist intended and how do you know even then that any deviation from that is not due to the many other things that can affect the sound waves that reach your ear drums?

Reading all the preceding posts and the handwringing and tying oneself into knots is a classic example of a first world problem caused by/for gullible customers of purveyors of digital snake oil - it is amusing, and also sad because this speaks to universal human failings.

I’m not going to stoop to that level of criticism, but beauty really is in the ear of the beholder and I hear an immense difference.  It does depend on your source and system.  There’s a reason every streaming provider is jumping on the hi res bandwagon, but there will always be old schoolers who are happy with low res, and that’s ok.  As a studio musician for my whole life, I’ve seen the demands that recording artists put on the engineers to get the sound a specific way, and they definitely weren’t mastering to mp3.  Let’s agree to disagree, I wish you all best Kumar.

I am fine with agreeing to disagree; I have found that arguing over Hi Res audio tends to be like doing so across as big a chasm as religion v science, as an example, so that is a good way to go. I will just pick and make one correction where you seem to say that low res works for me. It does, but only if you define CD format/quality as low res - which it is but only in comparison to high res in terms of bits and bytes of data it contains. But 16/44 CD quality is as good as it needs to be for me and for those that do not partake of the Hi Res audio thing.

I also know that mastering engineers master using more bits than 16/44, and I also know why they do this and that this has nothing to do my being able to get better sound quality than CD only from Hi Res audio.