I was wondering is it possible to replace the speaker on the ps4 with lets say...a different kind of speaker or no speaker at all.
I'm sure you could just remove it and it would work fine, and you could definitely replace it with a different speaker. What are you looking to do?
Maybe you could even use a ESP8266 or ESP32 to change the sounds over WiFi? That might be a lot of extra work though in comparison, but it would be cool!