$ ls *mp3 | xargs mplayer Playing Lemon. File not found: \'Lemon\' Playing Tree.mp3. File not found: \'Tree.mp3\' Exiting... (End of file)
find . -name 'Lemon*.mp3' -print0 | xargs -0 -i mplayer '{}'
This helped in my case to delete different files with spaces. It should work too with mplayer. The necessary trick is the quotes. (Tested on Linux Xubuntu 14.04.)