My original Chromecast only lasted about six months and even then, it would require being reconnected each and every time it was used. I would hope the new hardware is more reliable.
Anyway, there is something called BubbleUPnP Server that can be installed on a NAS to provide additional connectivity on top of a DLNA/UPnP server. It works in tandem with BubbleUPnP on a device. It is available as a Synology module, so I don't know if it is available for others, or what it requires. I do not run it, but keep it installed (and inactive) so it is ready to go if I try another Chromecast. As I have a best buy gift card, I might pick up the Chromecast Audio to use on a remote system, so I can stream my NAS files.
I will be curious to see if Chromecast can play 24/88.2, 24/176.4 and 24/192 files. I had another media player that simply would mute when playing some of these files, while it would downsample others. I don't care if Chromecast downsamples, as on a remote system the sound quality is not the #1 priority. I just don't want it going mute if it comes across a sampling rate it does not normally handle.
For remote systems, I just found it easier to run BubbleUPnP on a device, then use one of those Bluetooth audio adapters with the NFC connection feature--just tape the device to the Bluetooth receiver and it pairs/connects. Bluetooth audio doesn't sound the best but again, on a remote system like an old boombox or kitchen audio system as background music, it will not be noticed. It is a lot less bother, actually, since there is no worrying about sampling rates, network connectivity, etc. (Maybe I just talked myself out of buying the Chromecast Audio...again.
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