I'll try a new post for this:

I need some way to control the audio output on my soundcard via software. Are there programs that will limit frequency ranges? Unfortunately, the computer I need this on only has onboard audio, and I don't think there's any "advanced" software for it (I've spent a couple hours checking).

Thanks for any help.

ps- If I have a 10W amp feeding 15W speakers, is there such a device that I can use to boost the power level up in-between?