Actually, the proper way to use Lumin app is to use MinimServer, instead of using USB storage. If you use a NAS to store the music files, install MinimServer to the NAS. If you use a computer to run Roon Core with the music files in the computer hard drive, then install MinimServer on the computer. Either way should allow you to share the music library in both Roon and Lumin app.
If you have MinimServer, in Lumin app, choose Library and select MinimServer.
If you have connected a USB flash drive to the Lumin player/transport, choose Library and select LUMIN USB Music Server. With this method browsing is much slower, and album / artist / genre views are not available. This usage is also not recommended when you use USB output to DAC.
I actually donât use Roon even though I have a lifetime license. I donât see the need for it. I donât care about anything it does not related to sound quality. I also donât really care about upsampling, DSD, etc. PCM is fine for me.
I guess I donât know al lot about this but it just seems that playing music from a device that travels through my house along ethernet and into my router cant be an optimal way of achieving the best sound quality.
L1 is easier to use than NAS + MinimServer, and has matching aesthetics to Lumin players.
L1: Connect a USB cable between the computer and the L1, copy ripped music or downloaded files to it. Safely eject the L1 as USB HDD. Then unplug the USB cable. The Ethernet-connected L1 reboots into network UPnP server mode and appears in Lumin app as a selectable library on the network.
MinimServer: copy files to the machine running MinimServer. In Lumin app, invoke MinimServer Rescan.
USB device: just plug a USB flash drive (with a single partition only) into Lumin U1, then select LUMIN USB Music Server in the Lumin app library selection.
Both Roon Labs and Lumin have the position that Ethernet offers better sound quality than other typical means like direct USB connection to a DAC: https://kb.roonlabs.com/Sound_Quality