I too am without sub (boo hoo). I have been planning to buy one for around 10 months now, but never seem to get round to it due to various money reasons.
I have quite large bassy speakers all round at the mo and used to be quite happy with them in my Pro Logic setup, but as soon as I made the jump to digital I realised I was missing something. I demo'd a Rel Q50 and I new I HAD to have a sub to truly appreciate how a movie was supposed to sound.
I answer to your question on settings. I have my front and rear speakers set to large with the amp routing the LFE to them. The centre is set to small as, even though it is basically the same model as the rears, it just dosn't sound right set to large.....experiment and see which sound best to you...but remember to route the LFE to the speakers set to large.
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