thank you for the advice. i feel not bound to the se amps. if the output impedance is not low enough to drive the woofer i would use my current push pull mono blocks with 4x el519 and plenty of power and low Zout or build a hybrid amp for the bass with mosfet power follower to deliver the current in the ouptut stage.

yesterday i calculated some horns and they get really big...(i can not use a wall for each channel)
i am not sure if there is enough room to fit them in. it would be great if you could send me the plans of the 10 Pi horn.

thanks
peter