I am thinking about having rear surrounds in a 5.1 system put in a drop ceiling and am wondering if it is important to have the rear speakers match the fronts or if it is ok for them to be completely different. I realize people often say that the front L/R and center should all be from the same manuf, or match in timbre, but I wonder if this is true of the other surrounds or if they can be completely different? I am thinking about the HSU Research Hybrid 2 5.1 package but minus the rear speakers and then getting something else to put in a drop ceiling for the rear. HSU makes an in-wall that they claim can go in the ceiling but there is no enclosure on it and they suggested I might build an MDF enclosure for it. That doesn't fill me with confidence on that particular speaker so thought I might go with another designed for the task, Polk and other's make some which are enclosed for the purpose.