I've been running the u89's for about 4 years now and have consistently found them to sound better with the 80Hz rolloff turned on. I ran my u89's for the first time under the guidance of Dan Estrin during the summer Phish tour of 2000 and I remember him saying that he always ran with the rolloff activated.
BTW, there were some u89 pics from Big Cypress circulating a few years ago. I'll see if I still have them.
-Bryan
+t for your panic fob from colimbia. I patched out of you. those tapes smoke :afro: