A really obscure forgotten audio format: “Talking rubber”

There are several things going on here: first, what is the “talking rubber” technology? After talking to several historians of science and technology, I’m pretty sure it’s not a term that ever caught on. But it turns out that’s because this actual technology never caught on; although on first glance, this ad seems to describe magnetic tape—the technology behind cassette and VHS tapes—“talking rubber” describes actual rubber, not tape! In 1952, The Bell System Technical Journal chronicled “a magnetic recording medium composed of rubber impregnated with magnetic oxide and lubricant,” that was “particularly suited to applications requiring the continuous repetition of short transcribed messages.”

From A really obscure forgotten audio format: “Talking rubber” | Ars Technica