I've just bought a new HIFI and thought I'd link the computer to it (they're 20 feet apart). After loads of cable fiddling I get it going only for the music to sound like the speakers (warfdale) have been placed twenty feet down a steel pipeline (all tinny with loads of echo). I tried it again with a shop bought 1 metre cable which produced the same sound. Now when I put the headphones in the computer's headphone socket I get the same metallic echoeing. My computer is a Packard Bell and the soundcard is the original (computer is 3.5 years old). Any ideas?