No, any folder not marked hidden will show on the phone - even folders marked invisible will show on the computer. (Folders that need root won't if the ROMs not rooted - you can see the base folder in the phone, but there's nothing in it.)
If you're talking about music showing in a particular app, but not on the computer, it could be DRM-protected music - that doesn't get saved like regular music files, or under the name of the music - and you can't move it to anywhere else (it's protected).