I noticed this the first day I bought them but wasn't sure if it was a problem. All of the midrange drivers SEEM to be working in my RTA12C's. They produce sound at least. In a particular scene in Transformers 2, the sound shifts to the front 2 speakers and during this transition, the RTA's sound somewhat distorted, at least compared to my other speakers. This apparent distortion is only noticeable on this one scene in this one movie.
I was messing around with my "new" Monitor 7's(thanks intangible) and decided to compare them to the RTA12's. I moved them up front and listened to the same scene from Transformers and no distortion. I thought it was weird so I decided to try the push test on both RTA's. When I did, I heard/felt scratching on EVERY midrange driver. I did the same to the Monitor 7's and absolutely no scratching.
When I push the drivers in on both sets of speakers, the passive radiator moves with them. I can't remember but I thought I read that if the drivers were blown, the passive radiator wouldn't move during the push test although I've done so much reading on these speakers over the past week that I could have gotten that info mixed up.
I hope there's nothing wrong. I want to upgrade the tweeters as well as the crossovers but if I have to spend more money to replace all four midrange drivers then I think I'm going to have a meltdown. My fiance will probably kill me first, though.