Daniel,I"m shocked! You must get good cables immediately. Any effort at good sound a reasonable price is undermined by cheap cables. Start with speaker wire if you don't want to change them all right away. Tributaries are about $3. a foot. Try the Monster XP on the longer lengths like rear surrounds to lower overall cost.
Then try at least one good interconnect. Spend at least $30-$100 on one pair.I bet you will change the rest of them shortly thereafter.