+1 Bombaywalla (with a slight qualification as described below).
Richard, I see that you are using some rather expensive interconnects and speaker cables. In part for that reason I would reiterate my earlier comment to the effect that you wouldn't have to double up on interconnect cables to implement a vertical biamp configuration. You would just use a short XLR y-cable at the inputs of the amp, such as one of those I linked to earlier, in conjunction with the same interconnect you would use for bridged mode.
You may have seen people claim at times that use of y-cables or splitters in their system resulted in some amount of sonic degradation. My strong suspicion is that in most of those cases the reason for that was not the y-cables or splitters themselves, but rather the inability of the component supplying the signal to drive the two sets of load impedances that were involved, and in many cases two sets of cables as well, in an optimal manner. That won't be an issue in your situation.
For example, it is sometimes reported that poor results are obtained when a y-adapter or splitter is used to route the outputs of a preamp to both a power amp and a powered sub. In those situations it tends not to be realized that the capacitance of the cable to the sub, which is often substantial due to the length that may be involved, will affect the signals received by the main power amp just as if it were added to the capacitance of the cable to the main power amp. It also tends not to be realized that the line-level input impedance of many and probably most powered subs is quite low, which will also affect the signals seen by the main power amp, especially if the preamp's output impedance is high. Yet the y-adapter itself will often be blamed for the less than optimal results.
None of those kinds of effects will be applicable in your situation, given also that the RCA outputs of the Bricasti DAC, which I assume you are using to drive your subs, are driven by output stages that are fully independent of those driving the DAC's XLR outputs (that often not being the case with lesser designs).
Finally, the very low output impedance of the Bricasti DAC, the fact that its connections to the amps are balanced, and the relatively short lengths that are involved, all work in the direction of reducing sensitivity to interconnect cable effects and differences. Including the effects of balanced y-cables that may be in the path.
Regards,
-- Al
