There were many things going on at the time. Digidesign made the Sound Accelerator boards for Mac and Atari in 1988 or so? Roughly contemporary to this. I don't remember the exact year, but I think the first instance of commercial 3rd party plug-ins for a software platform is Waves's dynamics plug-ins for Digi's Sound Designer editor. These ran (non-realtime!) on the 56k DSP on Digi's expansion card for Mac (I don't know if the plug-ins were available for Atari).
