I give up on Spectral Noise Reduction. It doesn't work on Mac Pr.
I've got BIAS Sound Soap installed on my Mac, and it works in all my other VST-capable apps (SoundTrack Pro, Digital Performer, and FCP), but not in Pr 5.5 (Adobe doesn't support the use of third-party plugs, but according to the documentation, they should work.).
I copied the .vst plug in into the Pr >Show Package Contents >>> VST Plug-ins folder, where all the other audio effects reside, and Sound Soap (and the other two VST plugs I had copied) aren't showing up in Pr.
Any ideas on how to get them to work?
That VST is most likely not a 64bit VST. Pr 5.5 is a 64bit app and only will run 64bit VST plugins.
That's not the complete truth. You can use a plugin called "jbridge" which makes it possible to use 32-bit VST plugins in 64-bit hosts. It works pretty well - no problems with my 32-bit VST plugins in CS5.5.
That certainly might be an option, but some VST's just do not work in PrPro. It depends on the particular VST's.