This is the "extreme" basshead setup I use for Windows. This is most likely not the most optimized solution, but this is how I do it. I posted this in the SZ2000 thread, and is here because Hawaii says so. Please share yours as well!
Foobar's built-in EQ is very limited. A parametric equalizer would give you the most freedom. If you're already using Windows (Vista, 7, or 8/8.1), you should get
Equalizer APO. Here is
a head-fi thread dedicated to it. Basically, Equalizer APO allows detailed control of the built-in Windows sound modules, so it only installs the controller (no GUI) and you set the settings in the file "config.txt" under "C:\Program Files\EqualizerAPO\config". Any changes you make in config.txt affects the sound in real-time. You can read the head-fi thread for very quick tutorials, but I promise that it only looks complex at first. Inside my config.txt is this:
Filter 1: ON PEQ Fc [COLOR=FF0000]25,0 Hz[/COLOR] Gain [COLOR=00FFFF]15,0 dB[/COLOR] Q [COLOR=00FF00]1,000[/COLOR]
Filter 2: ON PEQ Fc [COLOR=FF0000]3000,0 Hz[/COLOR] Gain [COLOR=00FFFF]5,0 dB[/COLOR] Q [COLOR=00FF00]1,000[/COLOR]
Red is the center frequency in Hz (comma means decimal), blue is the level, and green is the width of the curve (when using "Q", 0 is the widest, and affects the entire spectrum, while 10 limits the boost to just the center frequency). Filter 1 boosts the bass at 25Hz, which is my preferred depth (you can experiment on your preference). Filter 2 compensates for the recessed midrange of the HA-MR77X.

Some head-fiers made a GUI for it, most used is jiiteepee's FPEQGUI-10MC,
head-fi thread here. Using the GUI, Filter 1 above looks like this:

If you want to try the built-in Bass Boost in Windows (your sound card driver may or may not support this), try the following:
The 50Hz bass boost won't sound good on the "
Rah" track though, since the bass is already boosted in that song (which is why it's a great basshead test). Combining the 50Hz bass boost with Equalizer APO turns most songs (with bass kicks) into basshead tracks. Imagine that deep thud from Rah going 300 beats per minute in a death metal song (try
this).
I'll try to get JetAudio for PC again as I haven't used it in a while. I already forgot how the X-Bass effect sounded like.
This PC setup is actually based on my Android setup, which uses JetAudio for Android and the built-in DSP Manager for Cyanogenmod 10.