Is the curve for the Bass Boost under the “Bass and Treble” Effects section the same as the Bass Boost curve in the “Select Curve” section of the Equalization section under Effects? The bass boost under the Bass and Treble section only shows a slider for increasing or decreasing the db of the bass but doesn’t show a curve.
They are similar, but not identical. An easy way to see the curve for Bass and Treble (or any other filter) is to apply the effect to generated white noise http://manual.audacityteam.org/o/man/generate_menu.html#noise and then look at the result using “Plot Spectrum” http://manual.audacityteam.org/o/man/plot_spectrum.html with the “Axis” option set to “logarithmic”.