I remember Jensen. The first speaker I ever bought was a Jensen in about 1960. 12" with a coaxial shrieking horn tweeter. I made its wood enclosure and I drove it with my Heathkit vacuum tubes amplifier.

 

Thanks Joe! That looks like a really cool book.

 

I have been also need that because I have a app that do the bajar youtube in the form of mp3 or audio in the language of spanish.I want to test those converted music.