VSTi Host 3.0 (Mac, $35), from Defective Records, is a standalone application for using VST Instrument and effects plug-ins. It allows you to use plug-ins for performance as well as for processing live or recorded audio without launching your sequencer or other host application. VSTi Host was created in Cycling '74's Max/MSP but is self-contained; you don't need Max/MSP to run it. You can download a demo from Defective Records' Web site (www.defectiverecords.com). The demo quits after ten minutes and inserts a periodic squawk into the audio stream.
VSTi Host is easy to use and nearly self-explanatory. It stacks five VST insert slots: the top one is for a VST Instrument and the remaining four are for VST effects plug-ins. Send sliders allow you to send any mix of two audio sources — the VST Instrument and live or recorded audio — to each of the VST effects. Balance sliders crossfade the output of each effect between the input to the next effect and the final mix. The output is a mix of the two sound sources and the effects output bus.
VSTi Host's mixing network lets you create quite complex signal paths. For example, you can apply completely separate processing to an audio-file player and a VST Instrument, and you can route the plug-in outputs in parallel or series.
A number of features have been added in version 3.0 (upgrade for version 2.0 users, $10). The program provides an onscreen keyboard for occasions when you don't have a MIDI controller available. You can record the output directly to disk in AIFF format. ASIO support has been added, so you're not limited to Sound Manager and Mac AV-quality audio. At present, OS X is not supported. ReWire and DirectConnect support has been announced for a future update. For quick testing of VST plug-ins and fast setup recording, VSTi Host is well worth a look.