Last December Synology published DSM7 beta. In this new version of Synology’s operating system it is no longer possible to playback music via the USB port of DiskStations. That’s because the necessary audio drivers (ALSA) are no longer availlable in DSM7.
I am very disappointed about this. The last 2 years I use Roon on my Synology NAS to play music to a USB DAC. It sounds so well that a few month ago I decided to buy a new and faster Synology NAS. With the coming of DSM7 I now should have been looking for a Roon endpoint for playing music to my USB DAC.
I have created a feature request on Synology’s website (see this link). If you are also disappointed fill in this feature request too. My experience is that Synology listens to wishes from their customers.