I am having trouble understanding dialogue while listening to dolby digital DVD's. My center channel is a Klipsch RC-25 (two 5.25" woofers and a horn) and my reciever is a Harman Kardon AVR-635. I have the center channel set at small and the crossover set at 80Hz and have adjusted the gain to it +/- 2-3dB above and below all other speakers (all set at small and 80Hz) and that does not seem to help much. It seems like the other sounds coming from the center channel are making it difficult to understand dialogue - the dialague seems muffled or not very crisp. I do not have trouble understanding dialogue while watching tv, etc., just dolby digital dvd's. The reciever is connected to a Sony DVD player via an optical cable. The center channel is located above the tv in a built in bookshelf, but there is air space above, behind and on either side of the center channel and the front extends out beyond the shelft about an 1" to make sure the sound field from the center channel is not cut off. I have also 'angled' the center channel to make it point right at the seating area and that does not seem to make any difference. Are there any adjustments other than crossover and gain that will help boost dialogue or make it more crisp and understandable? Would adjusting treble, bass or delay's help any? Any suggestions/recommendations would be greatly appreciated.