TIL: What a first-order crossover is

We should all be pretty familar with what a crossover is, and what it does in an audio system, but in all my previous reading I’ve either glossed over or never seen a “first-order” crossover mentioned. So this article, which explains the pro/cons nicely in defense of Thiel’s decision to pull them from their latest speaker makes for a very interesting (and reasonable short) read on the topic.

 First, some basics for those who need them. The crossover is an electrical network that divides the sound into bass for the woofer and treble for the tweeter (and often midrange for a midrange driver). A two-way crossover has two filters: one that filters the treble out of the woofer and one that filters the bass out of the tweeter. (A three-way speaker adds filters that remove the deep bass and upper treble signals from the midrange driver.) These filters are characterized by the frequency at which they begin to attenuate a signal, and by the slope of that attenuation. A first-order filter attenuates at -6 dB per octave, a second-order filter at -12 dB per octave, and so on. These filters affect the phase of an audio signal, slightly delaying some frequencies relative to others.