find ~/Music -type f -mtime -145 | xargs tar -cvf backup.tar

tar: Removing leading `/' from member names
tar: /home/amonteiro/Music/UFOmammut/8: Cannot stat: No such file or directory
tar: (2017)/08: Cannot stat: No such file or directory
tar: -: Cannot stat: No such file or directory
tar: PSYRCLE.ogg: Cannot stat: No such file or directory
tar: /home/amonteiro/Music/UFOmammut/8: Cannot stat: No such file or directory
tar: (2017)/01: Cannot stat: No such file or directory
tar: -: Cannot stat: No such file or directory
tar: BABEL.ogg: Cannot stat: No such file or directory
tar: /home/amonteiro/Music/UFOmammut/8: Cannot stat: No such file or directory
tar: (2017)/03: Cannot stat: No such file or directory
tar: -: Cannot stat: No such file or directory
tar: ZODIAC.ogg: Cannot stat: No such file or directory
tar: /home/amonteiro/Music/UFOmammut/8: Cannot stat: No such file or directory
tar: (2017)/02: Cannot stat: No such file or directory
tar: -: Cannot stat: No such file or directory
tar: WARSHEEP.ogg: Cannot stat: No such file or directory
tar: /home/amonteiro/Music/UFOmammut/8: Cannot stat: No such file or directory
tar: (2017)/06: Cannot stat: No such file or directory
tar: -: Cannot stat: No such file or directory
tar: CORE.ogg: Cannot stat: No such file or directory
tar: /home/amonteiro/Music/UFOmammut/8: Cannot stat: No such file or directory
tar: (2017)/04: Cannot stat: No such file or directory
tar: -: Cannot stat: No such file or directory