Nexus Prime Audio Files (Ice Cream Sandwich)
The “ui” folder found in the audio file is a little more tricky to apply and is only for rooted users. You can apply the all new ui sounds (lock/unlock, audible selections, etc.) by replacing the “ui” folder located in the system folder on the root of your device (system > media > audio > ui).
- Extract the zip file (it should be automatically renamed “audio.” If not, rename the folder “audio.”)
- Place the “audio” folder in the “media” folder found on your device’s SD card. If there is no “media” file then create one.
- Choose ringtones and notifications from your device’s settings and the new Ice Cream Sandwich sounds should show up under their respective names.
(From Android Forums - Chris Chavez on October 22nd, 2011 at 12:10 am)