The original Apogee Dedicated Active Crossover was designed to take the performance of the Diva's to a higher level by (almost completely) replacing the passive crossover.

The addition of a DAX means you need 2 stereo power amps (or 4 monoblocks) as the woofer and midrange/tweeter sections are powered separately. The relative gain of the woofer amp against the midrange/tweeter amp can be adjusted by internal switches, the idea being you can use different amps for the two sections. (Amp gain can be ascertained by the input sensitivity, but I dare say a bit of trial an error in adjustments would be needed to get it just right)

The unit came with an outboard power supply which connected to the DAX itself by a long umbilical lead, the idea being to keep transformer noise away from the DAX/system. The DAX itself is standard component size roughly 19 inches wide, 12 inches deep and 3 inches high.

The unit has a 6 window light green digital LED display showing the settings of the independent left and right controls for:

Woofer level (0 to -6dB in 1dB steps)

Midrange/Tweeter level (0 to -6dB in 1dB steps)

Woofer to Midrange/Tweeter balance fine adjustment (-0.8 to +0.8 in 0.2dB steps)

Rake, high frequency, or 'brightness' adjustment) (±2dB @ 5kHz, in 0.5dB steps hinged at 1kHz)

The DAX works by taking the preamps output and using the internal circuitry to provide response tailored line level outputs for the independent woofer and midrange/tweeter amps. Originally designed for the Diva's it can also be used with Duetta Signature, Caliper Signature and Centaur Major by configuration of internal switches.

Other internal switches set the input to balanced (XLR) or single ended (RCA).

The balanced and unbalanced outputs for the Midrange/Tweeter and Woofer sections work regardless of the input type. This means you can set the DAX to unbalanced (RCA) input, and use the balanced outputs to connect to the power amps, or vice-versa.

The DAX2 was supposedly a simplified unit with a list price of $1995, dispensing with the front display and putting the power supply internally, I don't know of the existence of any DAX2 units, I think possibly it was never released and they produced the DAX3 which is the DAX1 simply without the front LED display panel.

Crossover modifications for use:

Diva - A fairly easy soldering job on the passive crossovers, changing wiring and the addition of a new midrange inductor, value 0.055mH denoted L5 full instructions in DAX manual

Duetta Signature - Removing backplate and swapping connections, Instructions in manual

Caliper Signature - Not so easy this one, would require cutting soldering wires

Centaur Major - As the Duetta a case of changing over internal wires