The other day I bought a set of Logitech X-540 speakers.
I use an HP Pavilion a1730n with Realtek on-board sound. The HP website confirms that this is a multichannel sound chip. The back of the PC has six different ports for sound input/output: Rear, Side, Front, Center/Sub, Line In and Mic.
The problem? The center/sub channel doesn't work. If I turn on the "Matrix mode" of the speakers (which is supposed to virtualize 2-channel sound for 5.1) the center speaker works, leading me to believe the speakers are just fine. I have tried everything I can think of with these sound drivers -- uninstalling/reinstalling, restarting, plugging everything in differently... nothing seems to work. I know that in older versions of the Realtek HD Audio Manager, you could reassign the connectors to different channels, but in the newest version of the software this is not possible. I can't use an older version of the software without disabling my audio completely as I am running Windows 7 and older drivers aren't compatible.
Does anyone here have any ideas on what I can try? I have tried multiple 5.1 sources as well as the speaker test in the aforementioned Realtek HD Audio Manager -- front left/right and rear left/right speakers test fine, but I get no sound in center or sub when I run the test for those.
Your help is greatly appreciated, I don't want to have to buy a sound card. ;]
Have you tried the drivers at RealTek? I had similar problems with my X-530 system. I downloaded the W7 drivers and everything's working, including automatic detection and assignment of the pins and jacks.