I often want to do something different to the frequencies of a sound above & below a certain frequency. A typical example would be to compress different frequency ranges differently or sum to mono the bass frequencies or something like that...
This little free plugin's pretty handy for doing that kind of thing, it just splits the input into 2 outputs, either side of a specified frequency. You can accomplish the same thing using one lowpass and one highpass filter, but this is tidier, plus you can sweep the frequency around easily while you're listening, to confirm it's all sounding the way you want.
[url="Simple Linkwitz-Riley Crossover" ]http://www.savioursofsoul.de/Christian/vst-plugins/effect-plugins/eqs-filter/#SimpleLR[/url]
Oops, looks like not all BBCode tags work. Oh well, the link is there for you to click on.