Forgot to add this....... I also developed in the early 80's, a rock sound system that could project 130db sound levels 300 or 400 feet. One of the first clear 4-way systems that included massive sub-woofers ( 8 McCauley 6244 woofers in Altec 210 cabinets, 16 McCauley 6326 Mid-range drivers and 24 Altec 288C's mounted on Altec 203B horns.) OUCH The McCauley woofers and drivers will soon be listed for bidding.