Comment 1 for bug 1581721

I don't think it's possible to combine the LPF and HPF filters in this way because the goal of the Model1 is that the DJ can engage both filters at once to limit both the high and low frequencies. With only one knob, one filter has to be unengaged while the other is active. But, we already have code for four-way eq (though it is not well-tested), so we could support this eq style that way.