If you don't have LADSPA (Linux Audio Developer's Simple Plugin API) installed, go and get it from the LADSPA-homepage and install the SDK. terminatorX requires ladspa.h.
Install terminatorX (see INSTALL)
Run terminatorX
Load an audiofile into the available turntable (you can add more turntables if you want) (Hint: Click on the button that holds "NONE" to load an audiofile, or drop one over the audiofile display from your filemanager if your filemanager is efm, gmc, Nautilus or compatible (kfm does not work))
Load a LADSPA plugin of your choice by clicking the turntable's FX button and enable it.
Click on the "Audio Engine"-button to start playback.
Click on the "Mouse-Grab"-button to enter grab mode. The turntable with the red border has the input focus.
Press SPACE or left mouse button to scratch.
Release SPACE or left mouse button to let the scratch-file run at the turntable's default speed.
Press ESCAPE to quit grab mode.