Sunny,
1)Does your mixer have a monitor send, or an effects send that isn't being used?
2) Does your mixer have a dedicated EQ, either graphic or individual on each channel?

If you answered "yes" to either ...... you still can benifit from my design. The master EQ does NOT affect the monitor send, so if you feed a signal to a bass amp - it will have independant control over tone.

An effect send will not be a separate feed (it includes any EQ changes made) but still can serve as a level of what is sent to the bass cab.

I tried to find your mixer on line, but had no luck. Give me a pic of the controls or a link to where I can see the features. I'm almost positive you can use my design with great success. A dedicated crossover is great, but it costs more and requires another power source anyway.