I'm used to work with rack mixers and I've got some others from another well known english brand. Any of them can play music material from SD or USB cards, and browse from control software. These can make live recording as well.
SL 16R can read 24 bits stereo wave files only, in both 44.1 and 48k rates. (without self detection)
So, to be able to play tracks, I need to change my tracks audio format from 16 to 24 bits, add "(00)" on the end of the name, and then copy each file in its own directory (regardless of the directory name however, but only one file in each).
This way, when I select the SD Card with UC Surface, All tracks are detected and can be played, but only one time, no possible sequence or loop, and it's quite impossible to browse this way within hundreds of tracks.
Playing music material is essential during venues, while setting up the sound system, and during wait times and public reception.
It should be a great idea to provide a simple directory browser to be able to use SD card as music player, an a great idea too, that the mixer could play at least, simple 16 bits wave files at 44.1k, wich is the most used file format on our planet !!
ideally, the player should be able to chain the titles in the same subdirectory, to avoid having to change anything every three minutes