Asterila

Asterila is a Winamp plugin designed to enhance the stereo field and ambiance of your music. It gives you the possibility to configure up to four triggers using simple expressions in a code similar to C (such as comments).

Set up and run the Winamp plugin

To be able to install this tool, you must have dsp.sps.dll in the Plugins directory of Winamp. After installing Asterila, you can configure it by going to the Preferences menu (press Ctrl+P), then Plug-ins and DSP/Effect. Double-click the Nullsoft Signal Processing Studio DSP entry from the list, then click Load and open the ZST - Asterila 2.1i.sps file.
Check the Enable processing box and adjust the sliders of the signal processing controls, or click Show Editor to enter the data required for changing the initialization or format, setting the slider change or initialization, as well as for specifying the per sample (or sample pair) information.

Adjust the stereo field and ambiance using simple expressions

When writing code, you should take into account that all variables are floating point numbers (no strings) and that the maximum length of a variable is set to eight characters, so anything longer than that will be ignored. Variables can be changed using various operators and math functions, which can be combined into expressions. Multiple expressions can be used by separating them with one or more semicolons (;).
Furthermore, extra whitespace (spaces, newlines) will be ignored. The predefined variables are nch (number of channels of PCM stream, which is either 1 or 2), srate (the stream's sample rate, measured in kilohertz, such as 44100Kz), slider1, slider2, slider3 and slider4 (the four previously mentioned sliders, each with a range of 0.0 to 1.0) and trig1, trig2, trig3 and trig4 (the four trigger buttons displayed below each slider, which should be reset to 0.0 when catching the trigger).

Takes a bit of time to master the code

Variables that can be modified by your per-sample code as well as all available operators, functions and constants are available in the help menu of Asterila.
All things considered, Asterila is a practical Winamp plugin for improving the stereo field and ambiance of your songs. However, it takes some time to learn the expressions.