I worked in an audio store in the late 70's. There was a speaker line that we picked up, that was made of styrofoam. They looked great, had an aluminum surround mounted to a flat base. Black grill fabric. The speaker panel was routed or molded to make different areas of frequency response. Multiple drivers. They sounded a bit hollow but were not terrible. They didn't sell well, either. I can not remember the brand name.
