Subwoofer cables - are they the same as normal analogue interconnects?


[1]
I have 2 svs subwoofers connnected to my Bryston sp3 (rca) by so called "subwoofer cables" of long length (5m+)  to get the run round the room.  I have relocated one svs to near the processor so I need a short length of just 1 metre. I have no specific shorter cables specifically described as  "subwoofer cables" but many decent standard type rca analogue interconnects. Are these cables basically the same, or am I missing something?
[2]
The sp3 only has one rca out marked as sub, but somewhere I can reconfigure an aux I believe. By mistake though,  I put the rca subwoofer cable into "rca centre" on the sp3 with what seems to be correct result - so one runs off rca sub out and one off rca centre out, all seems ok - I have them both on very gently. Again,  am I not understanding something?
Comments/hints appreciated
tatyana69