Your pre/pro should still let the subwoofer get some signal when the mains are set to large -- the sub still has to handle the "LFE" data on DVD's. As such, it should still send the sub a test tone. Is the subwoofer turned off on your pre/pro? (Oh, and what pre/pro are you using? -- somebody around here may know some tricks associated with it.) I would think you would need to leave your sub turned "on" at the pre/pro to properly route the LFE signal (the blurb on page 8 would probably apply to only rare cases, like older Pro-Logic receivers), but I'm not real positive since I haven't messed with an ICBM.

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