Macdonald 1958

Filed: September 9, 1958
U.S. Patent 3,061,675
Granted: October 30, 1962

James Ross Macdonald
"Loudspeaker Improvement"
[Claims 1-5], [Claim 5 ]. Diagrams:[Sheet 1] [Sheet 2]
Referenced by Walker in U.S. Pat. 3,773,984.