I've just bought the Mordaunt-Short Avant series (2 x 906 front, 2 x 902 rear and 905c), and have a 309 sub on loan for a while until our local distributor gets some more stock. This is all hooked up to a Marantz SR-7500 amp with 12 gauge Oxy Free cable. I've run these in for about 100hrs so far at various volumes. I'm having a really hard time with getting the Bass right in this setup. My room size is (wxdxh) 4.5m x 6m x 2.7m and I find I have a dead spot in the middle of the room. Unfortunately my lounge is in about that spot too. I've moved the sub to different places and cannot get enough punch without cranking up the sub volume until it starts to sound unbalanced. I've tried positioning the sub all around the room no no avail. I have it near a corner of the room now which is probably the best sound I can get from the 309. With respect to bass response, some issues I am finding with this setup are: * The center speaker sounds somewhat nasal and chesty voices just do not sound right, even after cranking up the bass to +6dB on the Marantz. For example, some male news reader voices sound a bit thin as compared to those from my high-end Philips TV. I have tried changing the crossover to get more low-end mid range to go through the sub with no avail. (I currently have it at 80Hz which is about right for the Avant 900s). I almost wish the Marantz had a +/- 12dB Bass control scale instead of the +/- 6dB. *There seems to be little lower mid-range without cranking the volume up to around -20. It almost sounds like a sub-sat package. Do any others of you have the SR-7500 Marantz with the MS Avant 900, and do you find the lower-mid range and bass response sufficient? Would the Denon 3805 been the better choice, or have I chosen the wrong sub? Although I really love the clarity of the 309W sub and the Avant 900s in general, should I change my order to a MS 909W for the dimensions of my room? I appreciate in advance any help offered.