Speaker Settings Subwoofer Crossover Not Working

I run a 7.0 speaker system connected in multi-channel analogue mode to my Creative X-Fi Titanium.

I set my speaker settings on Windows 8.1 disabling the subwoofer and checking the full-range speakers checkbox to allow the low frequencies to be handled by my satellite speakers.

I've made no changes to the settings and yet I suddenly experienced a decrease in bass after a system restart.

When I checked the speaker settings I noticed that checking/unchecking the full-ranged speakers and subwoofer checkboxes no longer made any difference. i.e. the signal still gets passed to the centre/subwoofer port on the soundcard.

Clicking on the subwoofer on the window, I can only hear sounds from my front left/right speakers. Previously, unchecking the subwoofer checkbox sends the low frequencies to the available full-range speakers.

I have tried using an optical connection on Dolby Digital and it gives the same problem.

I am running the latest driver version available.

Any suggestions?

That is not normally how a 7.1 system is connected/setup up. But if it works (worked) for you then I can't argue. However, what bass you are getting is controlled by the amplifier in the speaker system. If there were a change, something in the speaker system is the problem and probably not the PC.