I used to use 20 ft. interconnects and 8 ft. speaker cables, but found that a lot of vibration got into the source components. When I put the equipment between and behind the speakers, using 1.5 metre ICs, although it was much closer to them, the CD player, for example, picked up much less vibration. I suppose it's the difference between directly in the "line of fire", although 15 feet away, and off to the side, though only a few feet away. I can't say I've noticed any difference in soundstage, but I'm much less sensitive to that than to dynamics and resolution. In both positions, I had the components mounted on 1.5 in. MDF shelves mounted directly onto a brick wall. For what it's worth the manufacturer of my amplifiers (Museatex/Meitner) recommends long interconnects and short speaker cables, so it's clear that not even audio engineers are unanimous on this topic.
