Hi @dkissfan1, thank you for reaching out and welcome to the community.

Audio quality depends on the Audio format the Sonos system is receiving.

You can refer to this article Supported audio formats; essentially, the higher the bitrate the better the quality. 

Yes, we don’t have the Audio format display. However, the audio format you should be getting should be the same when using either the Sonos App or Airplay/Casting with the Amazon Music app.

It instead depends on your Amazon Music account type on what audio format you’re getting. e.g. Amazon Music HD offers lossless audio. Lossless audio is FLAC, ALAC, AIFF, and WAV. 

You can also contact Amazon to verify what your account is getting.

If you have other concerns, feel free to reach out.

If I am understanding you, since I have an Amazon HD account, the Sonos app will provide the exact same sound quality as airplaying or casting from the Amazon Music app. 
 

Are there plans to display music quality within the Sonos app so that we can be sure of what we are listening to? It would be very helpful. 

Hi @dkissfan1, yes, your understanding is correct.

It depends on the Audio format for quality.

I’ll be sure to tag this thread as a feature request as this is a piece of useful information to have.

For now, there are no plans to add this feature and tagging this thread for consideration on future updates.

If you have other concerns, feel free to reach out.

I don’t know where the new info comes from but the word has always been that you have to use the SONOS app in order to stream Amazon Music at CD-quality. This answer has been stated unequivocally in every other thread: Alexa cannot stream at CD-quality. 

I wasn’t asking about Alexa. I was secifically refering the best way to play “Ultra HD” content, now that Sonos has the ability to play 24 bit. 

Sonos can’t play anything over 24 bit/48 kHz and it can only play 24 bits from local content.  No streaming. 

There we go. Thank you.

You can’t play at Ultra HD AND, according to every other reply to the question about Amazon HD, you can only stream at CD quality when you use the SONOS app. Starting the music from the Amazon app won’t  do it. If you want the highest resolution available, you got to use the SONOS app. 
 

this is what I think Is wrong:

However, the audio format you should be getting should be the same when using either the Sonos App or Airplay/Casting with the Amazon Music app.

It instead depends on your Amazon Music account type on what audio format you’re getting. e.g. Amazon Music HD offers lossless audio. Lossless audio is FLAC, ALAC, AIFF, and WAV. 

Well, since Amazon’s “Ultra HD” is referring to the bitrate (24 bits) rather than the Kbs (96/192), you actually CAN play “Ultra HD” on this system. At least Amazon’s version of “Ultra HD.” So my question was whether the Sonos app played that natively, assuming, as you pointed out, that you are paying for the HD service. There is an audible difference between casting from the Amazon app and  streaming from the Sonos app, but I can’t tell if it’s just louder, or if it’s an actual resolution difference, and Sonos does not display the audio quality in the way Amazon’s app does (except when casting ‍♂️). 

No, you CAN’T play “Ultra HD” on this system  Sonos does not stream anything in 24 bit.  Period.  You can only play 24 bit sources from your local library. 

Thank you. It kind of seems like we’re splitting hairs over the same thing at this point, but your answer still helps. 

I don’t know if we can rely on the info from the Amazon Music app but on my side if I stream a 24-bit 44.1kHZ song it seems to play it as is on the sonos arc. (Sorry the screenshot is in French )

And what about the Ultra HD 3D? LOL. No seriously. 

Anyway, because all streaming services within Sonos S2 lack of functionalities vs their native app, I'm only using Airplay2.  

... which encodes at lossless 16/44, downconverting as required. But since that encompasses the range of human hearing you can’t have noticed any difference.