DSP (digital signal processing) is becoming more  evident in all areas of audio, especially as the cost comes down making it available to a wider audience. Traditionally 2-channel audiophiles have resisted the change to digital; in fact, the home theater people have been embracing the technology to a far greater degree. The pro audio segment first applied DSP techniques, in particular, of the use with speakers (analog active crossovers having been the previous standard for many years).

A little over ten years ago I imported a unit from DEQX in Australia. I still own it and Selah Audio was one of the first companies to use it with a speaker design. Other companies have now launched similar DSP products such as miniDSP. The benefits of a digital crossover and room correction were obvious to me so it was a no-brainer. Passive crossovers certainly can provide great sound but they still have their limitations. In some cases passive designs make more sense (simplicity and cost) but with more complicated designs such as line arrays DSP offers the best performance.

One of the common complaints against DSP crossovers is that the digital-to-analog converters (D/A) compromise the sound. With current D/A chips it's difficult to argue that there are distinct audible differences - yes I know some would argue they do exist. The question is how this compares with the advantages of using DSP, including smoother frequency response, room correction, and the ability to adjust the voicing of the speaker for your listening preferences. In my opinion these far outweigh any D/A issues which seem to mysteriously vanish with blind ABX testing.