From: Patent Tactics, George Brock-Nannestad
Eric Jacobs wrote:
> Found this RCA Orthacoustic patent filed in 1940 and granted
> in 1942:
> Correct me if I'm wrong, but doesn't this look like the
> Columbia Curve (1590, 318, 100 usec TC; 100, 500, 1590 Hz TO)?
> See page 3, item 6 in the above patent document describing the
> EQ characteristic.
----- this is the very same patent that Kevin Mostyn mentioned in his first