What is another name for a 6dB/Octave crossover?

A 6dB/Octave crossover is commonly known as a 1st Order Filter. This designation comes from the fact that a first-order filter provides a slope of 6dB per octave. The term "first order" refers to the filter's response to frequencies, meaning that for every doubling of frequency, the output power is reduced by half (or 6dB).

In the context of crossover networks, a first-order design is the simplest, involving a single reactive component, either a capacitor or an inductor, which shapes the frequency response. The characteristics of these filters, such as their relatively gentle slope, make them suitable for certain applications where a mild transition between frequency ranges is desirable.

Other filter types, like second-order and third-order filters, use multiple reactive components and produce steeper slopes of 12dB/Octave and 18dB/Octave, respectively. A bandpass filter serves a different function entirely, allowing only a specific range of frequencies to pass while attenuating frequencies outside that range, which does not align with the specifications of a 6dB/Octave crossover.