Turning the speaker config to 'small' did the trick.

Incidentally, for those that contributed to my question about driving a second set of mains, I purchased a Cambridge Audio P500 Power amp.

The sound coming out of that thing (from the pre-amp out of the 1050) blows the doors off my dear old Outlaw, but actually gave it a new lease of life.

Why upgrade the whole shebang when the $200 power amp gives such nice sound?

Thanks everybody.