That’s how the wp_localize_script function works. It prints all the variables before your script is included to make sure that the variables are available to the script. If you want to print the localized variables only one time, but make sure that they are accessible for all three scripts – you can do that by setting dependencies when enqueueing/registering your scripts. So, register the 'audio' and 'preloader' scripts with dependency set to 'shutter' (WordPress will then make sure that 'shutter' is included before 'preloader' and 'audio'), and then localize only the 'shutter' script.
