Couple of things I can answer there Scott. There is a speaker which is added on and runs right along the back of the keyboard....good sound quality too.
KN7 styles most definitely do NOT work in the Korg PA4X and would need some software to convert from Technics to Korg...not cheap.
Basically the PA4X is another Arranger keyboard employing the latest technology such as USB memory sticks; touch screen etc but with a totally different operating system to the Technics range of friend has one and I need to think differently when doing a set up to play a song.
Roger M