Let's take a look at the construction features of the dbx 223. At first glance, you'll notice the units are great looking. As you turn the controls something else becomes apparent; these units are extremely well built. The controls exude great precision, and the feel is a solid "click". Also, when you open the box, you won't find the external power supply that accompanies most processors in this price range. That's because dbx knows how difficult external power supplies can be to work with and even though it costs a little more we put the high quality power supply right in the unit. All the inputs and outputs are TRS differentially balanced 1/4" jacks that are bolted down to the chassis. This "nutting down" of the jacks insures that even if someone stomps on a cable plugged into the unit, it's not going to tear up the circuit board inside. All dbx crossovers all feature Linkwitz-Riley 24 dB per octave filters, the professional standard. But then again, what did you expect?Via a switch on the back panel, you first select whether you're operating your system in stereo 2-way or mono 3-way. Then you also set, on the back panel, whether or not you want to mono sum the LF (subwoofer) out. (Most systems that use a subwoofer are mono subbed to take advantage of amplifier power and because low frequencies are non-directional.) Back panel switches allow you to select the range of the crossover frequencies individually for both channels. The crossover frequency controls have ...