SJ, reading your description of the two types of sound imbalance you experienced raises the possibility that the midwoofer on the right speaker is either way down in volume or not working at all. If a sound such as a singer or radio announcer supposed to be in the middle is way off to the left that means that the voice frequencies are much louder on the left speaker.Also, a speaker whose midwoofer wasn't operating correctly would indeed sound quite shrill.
Switch the left and right speakers to see if the soundstage shifts and you might also listen to each individually in mono to see if there's a decided difference. If so, speak with Joe.
