EMI 350

EMI 350 claimed 20Hz - 20KHz and was a later roll edge version of a 1960s combination speaker.  The EMI 450 was Lower Fidelity mock up of the 350 but at the time nobody knew anything about these speakers as they were sold only through application to the company directly.  A SALE was held when production stopped and that is how most people learned of their existence.  They did seem a lot of speaker for the money!