Sonos won't play Hi-Res music files. What are my options?

Sonos supports FLAC but the maximum sample rate can only be 48kHz. So convert the files to 48kHz/24-bit FLAC using audio software like Audacity.

Read more about what audio formats are supported for a Sonos music library here:

https://support.sonos.com/en-us/article/supported-audio-formats-for-sonos-music-library

Does the sound quality diminish though by reducing the Khz size from 96 to 48?

Not unless you are a dog, or a bat.  The sampling theorem used in audio states that all of the signal under one half the sampling rate is captured and reproduced exactly the same as the original analog signal, with no loss.  1/2 of 48 is 24 kHz.  The human ear cannot hear anything over 20 kHz, and if you are out of your teens, it’s far less than 20 kHz.  

By the way, if you are ever perusing audiophile sites, and you see anything about “jaggies” or “stairsteps”, or “digital is an estimate, and a higher sample rate gets you closer to the original” run away.  They are either ignorant, or lying to you, and neither one is to your benefit.  

There are no peer reviewed studies proving that anything beyond the CD sample rate of 44.1KHz can be perceived by the human listener.

In the studio, during production, there are benefits when the producer uses higher sample rates while processing the session, but there is no audible benefit using these higher rates for distribution to the retail listener. For anal producers, they should be operating at sample rates higher than 192KHz. 192K is lame if you are being anal.

A minor historic detail: SONOS has used 24bit internal processing since inception in 2005.

Aside from the higher sampling rates being inaudible snake oil, they would add to the communications load between speakers and services which would lead to increased dropouts.

It would be interesting to see some numbers from folks in heavily congested WiFi locations on the reliability of the various options, to include ATMOS when channel utilization is 60% or higher.

I have my local music at 16 / 44.1 as I, or a few friends I’ve asked,  can not hear any difference between that and the higher resolution ones.

For a music lover the only thing to understand about audio formats is whether they deliver better sound to the extent that humans can hear, and as said by others here, Hi Res does not offer that. Indeed, even Apple AAC, that is a format that compresses CD files, offers outcomes that are audibly the same as CD quality, something that is vouched for by the head of Apple Music.

Doing the one time exercise of resampling the Hi Res music you have, also as suggested, is all you need to do to hear music of the quality that is on those Hi Res files, via Sonos.

Music sold as “Hi-Res” can often sound better than the standard issue, but this is due to more careful processing, beginning with higher quality master tapes, not some sort of higher playback bit rate.

Some less than ethical producers will (at a premium charge) simply resample a regular CD in a “Hi-Res” format. At best, this release will sound no better than the original CD.

Also: none of the above gains will be lost via downsampling to a file that Sonos can play. And of course, if the quoted above has not been done, ask the question why you have paid extra for the Hi Res files in the first place.

Thank you for all your feedback, that’s really interesting to hear your views and will have a think before buying any more Hi-Res files.