Go to
http://www.behringer.com/DCX2496/index.cfm and click on software updates on the right and get the new OS and remote control software.
If you can connect a PC to the DCX setup is pretty quick and easy.
Setting up a subsonic filter (high pass) at 23 hz. is not hard, but you will have an issue setting one at 15. The minimum center frequency for filters is 20 hz, although the filter effects go lower.
As for the other filters, keep in mind the DCX can apply filters to the inputs and the outputs. If you want a filter to apply to both outputs, put it on the input to save work and CPU capacity.