extreme volume loss

I wanted to wire an extension to a box at the other end of the room. this is not successful, as the volume cable loss is extreme. the speaker was only audible if I had all the other finished. In my view, incomprehensible how one can produce so sound leakage through such a simple cable .. especially since one of the boxes had only on a thin wire strands hung directly connected but still full potential. could not return because I had already cut the cable.
so best the finger let it.