DSPRack is a real-time effect-processing software, running on Windows , which can process direct audio source thru native (DSP’s) or VST effects.

 It also provides a built-in loop processor that will play wav files in the background, while you play your instrument(with pitch shift and time stretch).

It requires an ASIO enabled input/ouput device with a fairly high quality device driver in order to operate with as small a latency as possible (delay between input and output). 

Beta 1.5 of DSPRack available to DSP registered users: go to MyPlanet.beta to download