Ditto on the responses above. The stock links or brass jumpers of most speakers are usually not too good. A short length of speaker wire will produce better results in most cases.
Kijanki made a good point about the connection at the speaker terminals. The quality of connection ie. tightness at the binding posts will likely affect sound quality as well. It may be more feasible to consider jumpers that have spades on one end and bananas on another end instead of using bare wires. A tighter and more rigid connection usually yields better sound.