Posted by Wayne Parham on August 21, 2002 at 12:33:44

In Reply to: Re: 2nd ordrer Butterworth vs 3rd order Butterworth posted by spkrman57 on August 21, 2002 at 07:43:40:

The values of R1 and R2 are usually the same when following a second order or third order of the same crossover frequency. But you might want to confirm this with Spice, because while I found it to be true on many of the circuits I tried, I would not assume that is always the case.

About the JBL 2226J (16 ohm version), Le=3.5mH and Re=12.0 ohms. Zobels are pretty wide tolerance filters, meaning component value shifts have a fairly small impact. I would suggest Zobel resistance of 16 ohms and capacitance of 8uF to 15uF.