Dean, Audyssey equalizes each speaker only as low as the crossover set for that speaker. For example, if a certain speaker crossover was set at 100Hz in the Audyssey process because of weak response measured below that number, manually setting the speaker to say 60Hz instead would mean that there would be no equalization for the 60-100Hz range. Raising the crossover to 120Hz or higher would of course still provide equalization for the range above 120 Hz.
My view is that the "plus" type of bass setting is a bad idea and that the mains and sub should remain separate, as the basic concept of bass management contemplates, to allow the sub to handle what it does best and relieve the mains of part of the burden.
