The gaggle of celebrated Stax artists were, at the time, much more popular in Europe than segregated America. This was due in part to appearances on music and variety TV shows in England and the like.
In comes The!!!! Beat, a Dallas-based music tee-vee program. As you can see above, the show featured thee voices in American soul and rhythm and blues.
For even more videos of The!!!! Beat, check out the YouTube channel of one Rachel Cummings.