I have an arbitrary-band biquad parametric eq I'd like to eventually release for foobar, but there are big enough warts with it that I'd like to hold off on a general release for now. I've been using it for several weeks now and it seems pretty solid in normal use, so at least it's not really unstable. If you are interested in jumping through some hoops to install it (including a several-megabyte runtime engine download), PM me and I'll get you set up.