Bruno, you probably didn't mean that you can't get LFE at all, but just to note that the mains do play(although with not quite the wallop of a good sub) any LFE present in movies when the sub is set "none".
Most receivers do not send the LFE channel to any other speakers when the sub is set to none. It was the practice in the very beginning of digital 5.1, but upon recommendation of Dolby it has been stopped. The problem is the LFE channel has 10 dB more dynamic range than the other channels (old receivers also got this wrong, even on the sub pre-out) and can't be directly mixed. Today's receivers when the sub is set to "none", the low frequency effects are dropped.
