I've been searching out examples of early bbx's ~ I Notice the mention of the Marantz Superscope (1st unit in the 1976-81 'birth of the boombox page) noted as being the earliest example to be found.

So far my contention is that the Sony CF-550 of 1971 fits as the earliest example ?

Other pre 1971 bbx's ? They must have the following features which seem to define 'Boombox'...be a portable with handle, stereo, at least two frequency bands, built-in condenser mikes, and of course be a cassette recorder/player.

Some of the units mentioned on another forum that date to the late 1960s were somewhat of a novelty, not a refinded product in a package such as the CF-550 that has the above mentioned features.

By definition does a BBX have to have 2 speakers and record/play in stereo?

Yes, I'd say 2 or more speakers, rec/play in stereo...but also at least have AM/FM bands. There were some assorted tape only portables in the late 1960's, but I'm thinking more of any units that fit the classic definition of bbx...suitcase style, radio/tape stereo. I think someone posted a photo of a Magnavox circa early 70's a couple of years ago, but couldn't find it.