Editing Audio crossover (section)

====Digital====
Active crossovers can be implemented digitally using a [[digital signal processor]] or other [[microprocessor]].<ref name="WilsonAdamsScott" /> They either use [[Digital data|digital]] approximations to traditional [[Analogue electronics|analog]] circuits, known as [[IIR filter|IIR]] filters ([[Bessel filter|Bessel]], Butterworth, [[Linkwitz-Riley filter|Linkwitz-Riley]] etc.), or they use [[FIR filter|Finite Impulse Response (FIR)]] filters.<ref name="SchuckKlowak1988" /><ref name="wilson1989application" /> IIR filters have many similarities with analog filters and are relatively undemanding of CPU resources; FIR filters on the other hand usually have a higher order and therefore require more resources for similar characteristics. They can be designed and built so that they have a [[linear phase]] response, which is thought desirable by many involved in sound reproduction. There are drawbacks though—in order to achieve linear phase response, a longer delay time is incurred than would be necessary with an IIR or minimum phase FIR filters. IIR filters, which are by nature recursive, have the drawback that, if not carefully designed, they may enter limit cycles, resulting in non-linear distortion.