Kiwi, I agree with Soundhound. Even though the manual for the 555II says you can use it in bridged mode to drive 8-ohm and 4-ohm speakers, any speaker that drops "substantially" below 4-ohms is not recommended. By the way, the manual says "...when any amplifier is operated in bridged mode, the load is split between the two amplifiers in the bridged configuration. Therefore an 8-ohm loudspeaker will be seen by the amp as if it were a 4-ohm load; a 4-ohm load will be seen as a 2-ohm load." Best wishes.
edited= you only have one sub and amp right?

[This message has been edited by steves (edited February 07, 2003).]