Do you want to customize your own musics as Ubuntu log-in and log-out sounds? Actually the thing’s easy, you just need to convert your musics to ogg format and have the super user privilege to open the file browser.
First, prepare ogg audio files. Use streaming audio recorder like outRec to create ones with ogg extension, and audios are recommended in 12 seconds (the sound won’t stop till audio finish) . Or, you can use winff to convert an exist audio file to ogg.
Then, open nautilus file browser with this command in Applications -> Accessories -> Terminal:
Give your user password, and nautilus opened up with the super user privilege. Navigate to
/usr/share/sounds/ubuntu/stereo, backup the desktop-login.ogg and desktop-logout.ogg. Finally, copy and paste your created audios into this folder and rename to desktop-login.ogg and desktop-logout.ogg.
As well as login and logout sounds, you can replace other sounds in the same folder.