How to connect powered sub to sound card?

[aznofazns]

Hello,

I just purchased a Velodyne VX-11 powered sub and I'm having trouble connecting it to my X-Fi Titanium Fatal1ty Pro sound card. I have BX5a Deluxe hooked up to the main stereo out port on the sound card (3.5mm to dual 1/4" TRS splitter) but when I connect the subwoofer to the center/sub out port on the sound card (3.5mm to white/red RCA) I run into issues. My Creative audio control panel detects the subwoofer when I set it to 5.1 mode (I can click on the sub icon and the sub will rattle) but there is 0 sub output when I play music or movies.

Here's what the sub's back panel looks like:



I currently have both white and red RCA cables from the 3.5 to dual RCA splitter plugged into the sub.

Any ideas?

 

[aznofazns]

This is what I did. I have the 3.5mm to dual RCA cable running from the sound card's sub/center out to the subwoofer's Red/White RCA inputs. Like I said, my sound card auto detects 5.1 mode, and the sub produces a rattle when I click on the sub icon, but no sound outputs when I play music.

Here's a picture of the sub:

 

[TheKillerPiglet]

Not sure if this helps, but it seems you are feeding both the center and sub out from the card into the subwoofer. Sub/center sends center channel to one RCA out, the other sub (mono) to the other RCA, but you are connecting as if it was L/R sub out. It's 5.1 so sub is mono.
 
In the PC's sound/speaker setup, try disabling center channel, hook only once RCA into the sub (try red RCA to top input), and play it. If that does nothing, then try with white RCA.
 
As a sanity check, you could run your L/R front from the sound card into sub and see if you get anything playing at all.
 
KP
 
edit: You can probably leave both RCA's plugged into sub, and in the setup disable center channel then use swap center/sub to test.