I purchased a 21THX about 2 weeks ago. Having replaced an older Bose system, I am overall pleased and amazed with this AVR's capabilities. Due to financial limitations I was only able to purchase fronts and a sub. I am running my cable box, BD, and appleTV via HDMI. I will not try to push AppleTV to anyone, but the one HD movie I own and having been testing with is Quantum of Solace, the audio and video (Panasonic 50S1) are sweet, the sound is foolishly loud and bass kicks, which works for me. The only issue and disappointment thus far is that when I play music (I can access iTunes) and non HD movies through AppleTV or non HD channels on my cable box, my sub will not engage, I will not even get the LFE to light up. Having the initial sub I purchased, defective, I scoured this forum, and all of your info has been helpful, but after trying what I think has been everything I can not get sub action other than from Dolby recognized sources. Forgive me if I am missing something, but if I am showing STEREO on the 21, should I not expect to get subwoofer action?