Question What is the storage capacity of the Ditto X4 Looper, when transferring WAV or AIFF files via USB to the unit Answer There is in total around 480 MB available when you connect the unit, but each loop will be approx 6mn max.  The limitation is also that you cannot access all the files you will store in the unit. Only the last loaded file can be read as at rack. there is no option to select a file as backing track on the machine itself.