I had a similar problem times ago; I tryed this way: unpack cache.psarc with the tool, than search for tone.json or something similar and open it with notepad, there you will find the default tone. Modify what you need and repack. Be careful make a copy before so you can come back if something goes wrong.
Great, it seems to be the right way; i open cache.psarc and search for tone.json. I modified it but maybe i make some mistakes or something goes wrong compressing the files and the game doesn't run. I put the original one at the right place and the things are ok; i will retry maybe tomorrow. Thank you very much It works! Thank you again @@Alex360