iPhone Backup -- Doubling Music Files?

[Hrothgar]

If I download 100gb of iTunes music onto my iPhone, and backup my iPhone to my computer, is that going to duplicate all of those music files on my computer? I.e., I have the music files in my iTunes library and then iTunes creates a second copy of the 100 gb files in my iPhone backup?

 

[Shirasaki]

No.
iTunes will try to sync your music back to your device if you are restoring from backup but those music are not included in backup