i have a HK avr 146. it has a subwoofer pre-out port (purple), but my polk sub only has the red and white rca ports....i thought i saw somewhere they had said to get a y-splitter...i simply cant find a male/male to male splitter...right now i have it connected using regular red/white rca plugs...red/white to red/white on polk subwoofer and the white connected to pre-out port on the HK avr, and the red plug is just hanging not plugged into anything....i get great bass, i think, out of it like this....just not sure if this is correct or if i could get better bass....

i am new at this, someone please help

Get the Y-cable even if you have to make one. You can always add a male-2female Y to two male-male RCA cable.

If you need a male to 2 male sub cable, there's a 13 ft gold terminated one in the factory buyout section of partsexpress for $4.
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=189-300