Have you tired booting the device off the factory repair disks? It is possible that the computer is trying to repair something that got corrupt and cannot due to the recovery partition not having that specific system directory. Also have you tried pressing the del key when the machine is booting up to see if any of the keys work?
Tweeters are the high freqs. Subwoofs are the low end freqs. What I might suggest is seeing what wattage your tweeters are running and finding an amp suited for them. It is better to run seperate amps for items like that.
Remember to shutdown the playstation 4 down though either holding down the power button until you see it go off or to shut it down through the ps4 console. I unplugged my ps4 on accident once and it killed the powersupply inside the machine. Also remember to blow out the machine every 6 months or so. Even if you are in a "clean" environment dust can still collect inside the machine.