My take on Onkyo speakers have no clarity

Being the owner of an Onkyo HT-s570, I've discovered a few things about Onkyo speakers. It is clear that my center speaker is less clear compared to the other speakers for dialogue, which kind of sucks since most of the dialogue in a movie comes from the center. I've tried switching the system from 5.1 to 4.1 to compare. During music playback, the difference is noticeable. During movie playback, it is quite bit harder to tell the difference. Since my center speaker has 2 drivers+1 tweeter vs. the 1 driver +1 tweeter that my other speakers have, I'm wondering if this has something to do with it? I know its probably not the fact that the speaker has 2 drivers, but maybe they are wired differently/use different componenets, which leads to the dialogue being less clear. I must say however, that I do find my other speakers to be very clear during music/movie playback. I've read all the comments regarding Onkyo HTib on this forum. However, looking at the systems being used,it seems that they're commenting on speakers which have dual drivers. Perhaps the statement: "Onkyo speakers have no clarity" should be changed to :"Onkyo speakers with dual drivers have no clarity".