Building a home theater.... mid-range supplied by 3 altec 291-16 horn drivers on 3 Selenium 56-50 horns....In designing the cross-overs the software asks for the FS, qms, qes, Re, Le, and z. of the 291-16's....my target is a 3 way 2nd order Linkwitz-Riley with a 800hz 1st x-over point..Any info on these parameters would be greatly appreciated