Crossovers, Active speakers, passive/digital.. All these terms can quickly become confusing! Here is our attempt to summarize speaker processing for multi-way crossover applications in few lines.
Passive speaker crossovers are typically located between the amplifier and the loudspeaker. They provide filtering at the amplified level (i.e. one amplifier channel per speaker) and have the advantage of potentially being low cost to manufacture.
On the down side, from the filter simulations to prototyping, few revisions & good electronic knowledge will be required to build a passive crossover that is well tune/matched with your speaker/amplifier configuration. The acoustic modeling of an enclosure + driver + crossover combo as a model (i.e. an estimation based on math equations) is only the first stage. Once in the real world comes the realization that "model" can only be "real" up to some extend. An extensive trial & error process will therefore be required to match your passive crossover to your enclosure. Add to this equation the knowledge required (electronic) and what sounded like an easy project with a couple of coils, caps will quickly turn in more than you can chew.
Digital DSP processed crossovers are on the other hand located between your source and the amplifier. They provide filtering at the "line level" and you will require one amplification channel per processed speaker. (i.e. 2way stereo speaker requires 4 channel). l
On the plus side, DSP crossovers such as a miniDSP are controlled from the click of a mouse and allow much great flexibility & accuracy. What used to require a Master in Electronics for passive crossovers is now a child's play with DSP crossovers. Forget about electronic design or PCB prototyping. A miniDSP platform will provide all the processing you need for all your most common speaker filtering application. Time alignment, phase control, equalization, steep filter slopes.. you name it!
Screenshot of miniDSP 2way Crossover control panel
Here is a diagram of a typical stereo 2 way configuration where a single miniDSP 2x4 platform provides all the processing required for the 4 drivers.
miniDSP + 2way plug-in configuration for Stereo 2 way system
Another obvious advantage of DSP processed speakers is the ability to "time align" a speaker, an important step to provide proper wavefront reconstruction and align the acoustic centers of multiple drivers in the enclosure. For more info on how time alignment works on miniDSP products, please read here.
This conclude this short introduction on the benefits of Digital Crossovers. To learn more about our products, see similar application notes below.