i think i understand how the horn and vented box work together now. The vented enclosure is tuned low and the cut off of the horn is a little higher. using the peaks from the event and the horn creates a bandpass type of response that is flat broad and effecient. If the horn cutt off is lower or the vented box is tuned higher than peak in the responce is created.
my next question if this is right how can you predict a peak in the box. say if the box is only going to be use for below fifty hzs. and you want more of peak below that use a larger horn bigger box ?