I recently upgraded my fronts from some JBL N28s to Athena ASF2s and the 250hz crossover that the Optimus SW12 comes with just isn't working for me. Athena suggests 50 hz on their own subs with the ASF2s. I have an Adcom amp for my fronts so the sw12, which is passive, is running solo off of my receivers speaker wire outs. What options do I have for reducing the sub frequencies? I would rather not alter the sub directly so an outside in-line solution would work the best for me. I am willing to spend up to $100 on this.