I use it on an iphone. I haven't tried to access that music through another music app ... I think what the synology app does is carve out storage space to be us

I use it on an iphone. I haven't tried to access that music through another music app ... I think what the synology app does is carve out storage space to be used for downloaded music based on the configuration you give it. For instance, if you're okay with 10 gigs of storage being used for music storage, it will do that, either in archival formats live .wav or .flac or in transcoded .mp3 and other compressed formats. You wouldn't really be handcuffed to the player if you wanted to switch in the future ... all the music is still yours and is housed on your NAS (with RAID for redundancy and preferably some off-site back-up as well). As someone else mentioned, VLC does the job as well (I use VLC for movie playback on my phone and love it). Synology is just really nice and easy to use, so I prefer it for music.