Aceboympk,
Its a tuff one... If you were to get the plate amps from parts express I suggest the ones that I believe have the parametric eq right on them. Its just like a 5 band or something which is really all you need and simplifies much more vs. the Rane.. Also you could recover the cost if that works out just selling the Rane on Ebay for 400 or whatever and you are even! You would be shocked even on this line array of woofers that 100 watts or 400 watts is really not a huge difference. The quality bass and blending I found was simply running the right setup vs. worrying about power or "what the optimal EQ setting is" because these speakers will react well with less finicky integration and "Lost bass nodes" if you simply run them as if they were one integrated speaker, thats why I suggest as many have go ahead and not be afraid to run these up in the 100 hz plus range, these are not Subwoofers in a conventional sense like Movies are rated for THX etc... To run 80 hz and below. Yes Zu for years have even themselves suggested running them at 40 hz which is where they designed the fronts to cut off, but believe me the Re-enforcement of the backs running you more full range giving you the "Punch" up above 80 and 100 hz definitely will most likely serve most recordings much better.
Again you have some decisions to make as to how easy or complicated you want to make this. Also how much really to spend. I can tell you whether you run a 100 dollar plate amp or a 1000 dollar combo pro rig you can end up with better than expected results depending on the room. Only issue is the plates and making sure they can be mounted and kept cool, if they are A-B type, which A-B vs. the Class D amps do sometimes sound much more robust and natural fill type bass. I mean I would for now see if you want to go with the Rane or not.
Is your Preamp XLR true balanced? If not than you might want to go the Plate amp route and eliminate converting back and fourth. If it is True balanced, well than you can keep it clean and make it all Rack gear using the Rane on top of a good XLR pro amp, it does not have to be a crown, as a matter of fact the QSC amps are a little cheaper and probably even better for the application with 300 to 600 watt ranges, but be careful there are many models and some can come with pretty loud fans, although most are 2 speed models that will not be noticed most of the time at low setting, and the Zu's really are efficient so they won't draw them that much. However again efficiency is a real trick here, has nothing to do with how overdriven an amp can get from driving an in-efficient load or even the impedance on these speakers which stays pretty stable at basically 8 ohms, probably dipping down in the 4 or 5 ohm range, but simply low frequencys will sweat an amp much more.
Best amp possible, My opinion although I would never spend this much even used on this application, would be a Mcintosh like 352 or 300... One that is true balanced, and they have relatively low damping factors around 100 - 200. They would really sound organic, but you would end up dropping 2000 to 3000 on an amp and not worth it in this application, so find something comprable otherwise. There are many used XLR amps around, but in the Audio realm over here vs. PRO you have to be careful they are really XLR balanced, not just a dummy jack that is XLR on the back, and that they are a higher input impedance, like I said I would stay with amp inputs of 20k ohms(20,000) or higher. Don't worry about wattage, but worry about quality and current drive, a 50 watt Class A amp would probably drive these better than a Cheap 500 watt Class D, but your talking more money.
If you really want to try a killer amp, the Monarchy Mono blocks are really sweet class A amps, true balanced, No feedback, will Crush those 10" drivers, but maybe just for plenty of Dynamic peak power you would want their like 100 watt per channel plus versions. They are also 100,000 ohm inputs, can be driven passivley with no preamp. So I think they would be excellent. Used you can get a pair around 1000 bucks, even monarchy might be running deals right now, but they do run very hot as they are 100% class A power, but would have an iron grip and sound like pure finess on these. I own a pair of the SM 70's which are sweeter but only 70 watts, they would work fine too, but driven off a Rane really putting them to the test with all super low frequencies I don't know the results. Oh and my monarchys in true balanced XLR easily beat the bass levels out vs. my Old Crown K1.. But totally different setup and applications. Remember my claims are only on very high efficiency and well impedance matched systems..No doubt 400 watt crowns in some speaker applications will be a better bet and run cooler.
Its a tuff one... If you were to get the plate amps from parts express I suggest the ones that I believe have the parametric eq right on them. Its just like a 5 band or something which is really all you need and simplifies much more vs. the Rane.. Also you could recover the cost if that works out just selling the Rane on Ebay for 400 or whatever and you are even! You would be shocked even on this line array of woofers that 100 watts or 400 watts is really not a huge difference. The quality bass and blending I found was simply running the right setup vs. worrying about power or "what the optimal EQ setting is" because these speakers will react well with less finicky integration and "Lost bass nodes" if you simply run them as if they were one integrated speaker, thats why I suggest as many have go ahead and not be afraid to run these up in the 100 hz plus range, these are not Subwoofers in a conventional sense like Movies are rated for THX etc... To run 80 hz and below. Yes Zu for years have even themselves suggested running them at 40 hz which is where they designed the fronts to cut off, but believe me the Re-enforcement of the backs running you more full range giving you the "Punch" up above 80 and 100 hz definitely will most likely serve most recordings much better.
Again you have some decisions to make as to how easy or complicated you want to make this. Also how much really to spend. I can tell you whether you run a 100 dollar plate amp or a 1000 dollar combo pro rig you can end up with better than expected results depending on the room. Only issue is the plates and making sure they can be mounted and kept cool, if they are A-B type, which A-B vs. the Class D amps do sometimes sound much more robust and natural fill type bass. I mean I would for now see if you want to go with the Rane or not.
Is your Preamp XLR true balanced? If not than you might want to go the Plate amp route and eliminate converting back and fourth. If it is True balanced, well than you can keep it clean and make it all Rack gear using the Rane on top of a good XLR pro amp, it does not have to be a crown, as a matter of fact the QSC amps are a little cheaper and probably even better for the application with 300 to 600 watt ranges, but be careful there are many models and some can come with pretty loud fans, although most are 2 speed models that will not be noticed most of the time at low setting, and the Zu's really are efficient so they won't draw them that much. However again efficiency is a real trick here, has nothing to do with how overdriven an amp can get from driving an in-efficient load or even the impedance on these speakers which stays pretty stable at basically 8 ohms, probably dipping down in the 4 or 5 ohm range, but simply low frequencys will sweat an amp much more.
Best amp possible, My opinion although I would never spend this much even used on this application, would be a Mcintosh like 352 or 300... One that is true balanced, and they have relatively low damping factors around 100 - 200. They would really sound organic, but you would end up dropping 2000 to 3000 on an amp and not worth it in this application, so find something comprable otherwise. There are many used XLR amps around, but in the Audio realm over here vs. PRO you have to be careful they are really XLR balanced, not just a dummy jack that is XLR on the back, and that they are a higher input impedance, like I said I would stay with amp inputs of 20k ohms(20,000) or higher. Don't worry about wattage, but worry about quality and current drive, a 50 watt Class A amp would probably drive these better than a Cheap 500 watt Class D, but your talking more money.
If you really want to try a killer amp, the Monarchy Mono blocks are really sweet class A amps, true balanced, No feedback, will Crush those 10" drivers, but maybe just for plenty of Dynamic peak power you would want their like 100 watt per channel plus versions. They are also 100,000 ohm inputs, can be driven passivley with no preamp. So I think they would be excellent. Used you can get a pair around 1000 bucks, even monarchy might be running deals right now, but they do run very hot as they are 100% class A power, but would have an iron grip and sound like pure finess on these. I own a pair of the SM 70's which are sweeter but only 70 watts, they would work fine too, but driven off a Rane really putting them to the test with all super low frequencies I don't know the results. Oh and my monarchys in true balanced XLR easily beat the bass levels out vs. my Old Crown K1.. But totally different setup and applications. Remember my claims are only on very high efficiency and well impedance matched systems..No doubt 400 watt crowns in some speaker applications will be a better bet and run cooler.