The VCA's in the 3BX-DS are mono triggered so dedicating one each to each channel (L & R) improves imaging, staging and definition. It also gives you the flexibility to adjust the channel expansion independent of one another.
I used 2 male RCA to a single female "Y" adapters (two per unit) giving me a single "mono" input on each unit. One for the left channel and one for the right channel. Not daisy chained. I suppose you could do it with XLR to RCA adapters.
Make sure the rear mounted trim pots for HF & LF transition are set equally on the units. You can tweak them as necessary by watching the front displays so you are getting the same level of expansion out of each unit. Having units close in manufacture dates helps too.
The 3BX-DS can be calibrated and adjusted using the Service Manual. Better capacitors in the power supply improve performance as well.
I used 2 male RCA to a single female "Y" adapters (two per unit) giving me a single "mono" input on each unit. One for the left channel and one for the right channel. Not daisy chained. I suppose you could do it with XLR to RCA adapters.
Make sure the rear mounted trim pots for HF & LF transition are set equally on the units. You can tweak them as necessary by watching the front displays so you are getting the same level of expansion out of each unit. Having units close in manufacture dates helps too.
The 3BX-DS can be calibrated and adjusted using the Service Manual. Better capacitors in the power supply improve performance as well.