Question Speakers really quiet using thicker wire

[Mistercrabby]

Hello. Stereo and speakers put out great sound using wires that came with the speakers. Thin, about the width of a pencil lead. I put same speakers on same channel to thicker wire that was already pulled through wall, over ceiling tiles and back down adjacent wall, maybe 30’. Very quiet, maybe 20% volume. There were two wires pulled. Tried the other, same thing. Any ideas?

 

[Mistercrabby]

Thanks for replying. That’s what I thought, about thicker wire. Connections are tight. However, I read elsewhere that the exposed copper can get oxidized, affecting performance. I’m going to cut the ends and redo them. The settings are the same. I’m just changing the wire. Thanks again.