Digital Active Crossovers -
Activation eliminates passive inductors,capacitors & resistors between the power amplifiers & speaker drive units making life easier for the amplifiers which only handle part of the audio spectrum but most of all allows the amplifiers to control the drive units much more accurately.
Here the Crossover filters are implemented using Digital Signal Processing (DSP). Advantages are different filter parameters can easily be tried, drivers can be time aligned, equalization of frequency response is easy, analog preamplifier can often be eliminated. Disadvantage is digital audio inputs have to be converted to a standard frequency before DSP, Analog inputs such as from turntable have to be converted to digital, after DSP the digital audio has to be converted by 2 or more DAC’s before feeding to the power amplifiers.
I was skeptical at first but the advantages are winning so far for me. My Apogee Stage speakers are now activated via a MiniDSP unit feeding 2 DDDAC1794 DAC boards and sound quality is better than the Analog Active I used previously with these speakers.
Pictures show custom frame for mounting Hypex Fusion FA123 Amp. Fusion Amps are vented for cooling so to fit in back of a speaker a sealed cavity would be needed. For retro fitting the custom frame allows mounting without affecting the cabinet volume and also allows for some vibration isolation.