I never had a servo problem with my IRS-V.
The servo circuit in the IRS is built into the woofer amplifier, not the crossover.
Hi Gary,
I may be mis-remembering, or getting mixed up, or just senile...
My IRS-II used the dual voice-coil woofer with a passive crossover. I remember it pretty well, and it most certainly did not have an amp built in. The crossover used both coils to help smooth out the impedance hump most speakers have in the low bass region. This was NOT the big IRS system, but the smaller single-cabinet (per side) system that was one step down from the top of the line IRS.
I do not recall if the original IRS used the servo circuit (in the amp, of course, you can't servo passively) or it was added later. In any event, my DIY design used the IRS woofer so I could use the second voice coil for feedback in my servo circuit (and I got it fairly cheaply since I worked for an Infinity dealer at the time).
Sorry for the off-topic'ness - Don
p.s. I have not heard of servo reliability issues in decades. There were some issues with some early implementations, but AFAIK any recent reliability problems are related to the amplifiers as has been stated. Again AFAIK the amps aren't any more or less reliable than any other amp; the servo circuit does not add much complexity. Probably the biggest issue with powered subs, any of them, is that they tend to get stuck where convenient and then hooked uop with long cables to the rest of the system. The problem isn't the cables but fact that the sub usually ends up on a different outlet, causing a ground loop. At least that is what I seem to see the most posts about on various fora.
p.p.s. That little single-band EQ is extremely useful to me. My Pioneer does not EQ the sub, and that Rythmik PEQ allowed me to tame the first room mode peak nicely. The other nice feature for me is the continuous phase adjust knob, which alllowed me to match (time-align) my subs with my main speakers. I run the subs in parallel with the main L/R speakers, after an active crossover, instead of using the LFE output and AVR's bass management. I had some problems with bass management in a couple of ealry AVRs, though most seem to have it right now.