Broken / Wrong settings - P900.5 Phantom

Hello peeps.

I've struggled with this for many hours, and now I leave it with you guys
I'm not a PRO, especially not with all the settings on an amplifier.

Background:
I want to upgrade my soundsystem from a 4channel amp to a 5channel amp of the same model, and then build a Cubo15 extendend. (you can see it in the video)

Problem:
The horns makes a high pith noise on the new amp (Precision Power P900.5). There's no problem when I use the old amplifier (p900.4).
I think the sound is a little stuffy, if that makes sense. Also I have a hard time hearing that theres coming some low frequencies out the 15" speaker.

So:
Maybe the amplifier is broken, or maybe i'm just too stupid to figure out the right settings for the p900.5 amplifier.

This is a video, bare with me for the really bad english and the danish accent

I hope you can help me out. I've got 2 months until Roskilde Festival kicks off
Cheers Rasmus.

a picture of the amps settings is attached