Here is from the manual:
TRIM: Set this to FLAT for normal subwoofer operation in a large room. The subwoofer will reproduce deep bass at normal levels from the movie soundtrack or music sources. The LOAD setting is for accessing the internal microprocessor. Do not use this setting as it will turn off the sub output and turn the light amber. The REMOTE setting is for operation with future Axiom remote controlled products that enables remote-control adjustment of subwoofer levels. If you are in a medium or small room you should experiment with Half and Full to compensate for room loading. Setting the TRIM to Half will partially increase frequencies above 33 Hz and Full will greatly increase frequencies above 33 Hz. This may be necessary to overcome room loading or boundary effect (too much low bass).
CROSSOVER: if you are using the Bass Management crossover menu settings in your A/V receiver or processor, turn this control to “BYPASS” to eliminate the EP500 or EP600 internal crossover from the circuit.
Also, I hope he used a Sub coaxial cable form the receiver to the sub, and not speaker wire?
