The 31 band eq can be tough, but if you use it more to tweak your tone for the room rather than actually shape the sound, it isn't really that bad. Honestly, a 15 band is probably more than enough. I wish someone would make a 15 band rack unit optimized for bass. I mean, who really needs 16KHz? :-)
First, you have to remember that generally speaking, boost=bad, cut=good. Leave as many sliders flat as you can. With the Ashly, at least, this removes the filter from the signal chain, minimizing the phase problem Joey mentioned. Then begin cutting frequencies that over-resonate in the room, which, unfortunately, are usually in the low end and can make your bass sound muddy and indistinct. Start by dumping one in the general area of the problem all the way out and then bring it back until it sounds the way you want it. Then go up or down as needed, one frequency at a time, until you have the tone you're looking for. If you're like me, you may want to give yourself a little bump in the 630-800 area (just 2-3 dB) to further improve definition and attack. Being methodical like this is slow, but it is great for training your ears and it is a great way to clean up your sound and give yourself more articulation and headroom.
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None of the above information in any way abrogates the fact that the SF-2 rocks total balls.
Charles