in the SP-404 manual it says in order to put a wav or aif file onto the memory card from your computer you must put it in the root level of the memory card. There is folders backup 1-9, back a b and c, and a roland sp- 404 folder. Which one is the root level folder.

The root directory is the beginning part (the root) of the disk drive. Here's a screenshot of my CompactFlash card's root directory in Windows Explorer to show you what I mean. Click on the thumbnail image to view the full size version in a new window.



I recommend that you name the files after the pads they will be assigned to because they will be loaded alphabetically. For example:


A_09--Bass_Drum.wav
A_10--Snare.wav
A_11--PD_Hat.wav
A_01--Crash.wav