John, is there any concern that letting the sub work above 90 (up to say 120) would cause localization of the sub? I would worry that letting a budget oriented sub work out of its prime zone and into a more localized frequency would degrade the image rather badly? That is one reason I tend to prefer my sub crossed at 45hz so it is only working in that area it is designed for, and where the towers (and amp) start to drop off.

Panny 3000 PJ, 118" Carada, Denon 3300, PS3, Axiom QS8, PSB 5T, B&W sub, levitating speaker wire