VST Plug-ins

Virtual Studio Technology Plug-ins are add-on tools,effects and synths that can be 'bolted' onto an existing audio host program. Audiomulch accepts VST plug-ins and this is how the Ambisonic encoding and decoding has been implemented. The VST standard was designed and is maintained by Steinberg.

VST plug-ins without a graphical user interface can be easily compiled for both Mac and Windows, allowing cross-platform operation. Also, the VST standard is so simple and the software development kit so easy to get off Steinberg, that there are many good, free, plug-ins available.

Links to Free VST Plug-ins

Surround Plug-ins

Ambisonics

University of Derby Ambisonic Decoder Plug-ins
Gerzonic 2nd Order Ambisonic Plug-ins
University of York Ambisonic Plug-ins

Other Surround...

AcousModules Surround Sound Suite of Plug-ins

Reverb Plug-ins

Ambience Reverb by Magnus @ smartelectronix
Freeverb Too by Sinus
SIR - Super Impulse Reverb by Christian Knufinke

General Audio Plug-ins

Kjaerhus Audio's Classic Studio Plug-ins
LiveCut by mdsp @ smartelectronix
Karma FX
Super Destroy FX
Gersic.com
Tweakbench VST Effects and Instruments
Broken Gadget VST
GVST Plug-ins - Free collection including high/low pass filters, chorus effects and simple synths
Live Cut Plug-in - Free plug-in that carry's out live beat-slicing. Very easy to use.
De la Mancha Plug-ins - Some free effects (and some you need to buy!) that mash up your audio in various ways!
Xoxos Plug-ins - Plug-ins where you choose how much you pay for them! Some nice physical modelling in here.