SoundCloud music which do not show up after syncing your SoundCloud account are likely due to files which do not meet our minimum requirements. SoundCloud files must also meet our requirements in order to populate, see details below.
WAV: 44.1khz, 16-bit, Stereo
MP3: 320kbps, Stereo
These are the minimum requirements when uploading audio files. You are allowed to upload 24-bit WAV's as well