I have a really nice Glockenklang UNO 1x15" cab. Id like to ad some highs to this cab by adding a Beyma 605Nd mid/high driver in a separate box. I think I will go with a second order filter but how do I choose the crossover frequency? Do I need to have a lowpass filter for the 15" or is it enough to use a high pass filter for the 6" ? Please help. Im quite new to this but I have read as much as I have found about this. Here is a link to the mid driver: http://profesional.beyma.com/ENGLISH/detalle.php?id=110 A similar cab by Hevos with a 15 and 6 crosses over at 2500Hz but I thought that sounds like too high on paper and I dont know wich order they use.