http://www.jblpro.com/press/nov08/JBL_Voishvillo.html Dual Diaphragm Compression Drivers - Audio Engineering Society Convention Paper :
https://secure.aes.org/forum/pubs/conventions/?elib=16028 \'\'A new type of compression driver consists of two motors, two diaphragm assemblies, and two phasing plugs connected to the same acoustical load (horn or waveguide). The annular flexural diaphragms are made of light and strong polymer film providing low moving mass. Unique configuration of the phasing plugs provides summation of both acoustical signals and direction of the resulting signal into a mutual acoustical load. Principles of operation of the dual driver are explained using a combination of matrix analysis, finite elements analysis, and data obtained from a scanning vibrometer. Comparison of performance of this driver and conventional driver based on titanium dome diaphragm is performed. New transducer provides increase of power handling, lower thermal compression, smoother frequency response, and decrease of nonlinear distortion and sub-harmonics.\'\'
Author: Dr. Alex Voishvillo
Affiliation: JBL Professional, Northridge, CA, USA
AES Convention: 131 (October 2011) Paper Number: 8502
Subject: Transducers and Audio Equipment
http://freshpatents.com/ \'\'Dual Compression Drivers And Phasing Plugs For Compression Drivers\'\'.
United States Patent
Patent No.: US 8,280,091 B2
Date of Patent: Oct. 2, 2012
Appl. No.: 12/895,606
Prior Publication Data: US 2011/0085692 A1, Apr. 14, 2011
Inventor: Dr. Alexander Voishvillo, Simi Valley, CA (US).
Assignee: Harman International Industries, Incorporated, Northridge, CA, (US).
http://www.google.com/patents/US8280091 http://www.google.com/patents/US20110085692 
