Is it feasible to run 2 cabinets per side from this amp (daisy chained)? Is this a fair match up, or should I seek aditional amp?
The QRx 115/75 is rated at 400W/800W/1,600W (Continuous/Program/Peak) and a nominal 8 Ohms. The RMX 2450 is rated at 450W/channel into 8 Ohms and 650W/channel into 4 Ohms. So with two boxes per channel that would be 325W per box.
That does seem a feasible approach since the amp should easily handle the 4 Ohm load and the speakers easily handle the 325W per box output. How that applies to your questions is not as easy to assess as whether it is a fair match all depends on what you are trying to do. If 325W per box gets loud enough for your use, then it is a good match. If not, then it isn't. If the goal is to potentially be able to get as loud as possible then it is probably not a great match as you are giving up about 4dB compared to the 800W Program rating of the speakers.
However, while more amplifier may help in many cases, you might also want to consider that going from one RMX 2450 amp with 325W per box with to two RMX 2450 amps at 450W per box should result in only a 1.4dB increase in maximum output, a difference that most people would typically not even be able to perceive. So adding a second RMX 2450 or comparable may not be the most effective option.
