I've got a pair of Paradigm Studio 20's that are less than a year old. Lately I've noticed some distortion in loud female voices and orchestral music in movie sound tracks (playing well below reference). I've isolated the distortion to the left speaker. Can somebody offer me some pointers on pinning it down to a particular driver (woofer or tweeter)? I'd like to be prepared when I contact the dealer and Paradigm for replacement.