Only bad thing, is if your monitors are on a higher bridge, like right in a null. I don't know how high you have your monitors or how high your ceiling is, but you don't want your monitors half way between ceiling and floor. You might have to raise your monitors past the half way point and angle them downward. btw, what are you placing your monitors ON. You might want to plan on leaving a hole in the platform sheithing, to build a stack of CMU (concrete blocks) directly on the slab for monitor stands. And then float your monitors on a decoupling pad. The mass of the concrete and the decouplers eliminate structural transmission to the rest of the house..and to your platform via the console, which will act like a membrane(if you are planning on sitting the monitors on part of the console). One other thing, are you dampening the sheithing in the platform....ie...overstuffed with insulation or sand? Might be a good idea. Those voids will resonate at a certain frequency relative to size of the void. Whether or not these resonances can be heard, why take any chances.
fitZ