Patent Review: Bose Transmission Line Loudspeaker

In this Voice Coil Acoustic Patents article, James Croft discusses an interesting Transmission Line Loudspeaker patent assigned to three engineers from Bose regarding an electro-acoustic driver and acoustic waveguide that includes “an enclosure, an acoustic transmission line formed within the enclosure, and a plurality of acoustic transducers contained within the enclosure and disposed along a length of the acoustic transmission line.” As Croft notes, this seems to be an improvement over the Tapped Horn loudspeaker architecture patented by Tom Danley, assigned 10 years ago. This article was originally published in Voice Coil, June 2015

James Croft reviews two loudspeaker-related patents as a tribute to David John Graebener, who passed away on January 3, 2015. First James Croft reviews the planar-magnetic electro-acoustic transducer he patented together with Graebener, followed by a single-end planar magnetic speaker system, David’s key patent. These were the first and second of the Single-Ended, Neodymium planar magnetic transducer patents David Graebener was granted. This article was originally published in Voice Coil, March 2015.

In January and February 2001, audioXPress included a project from Thomas Perazella, describing in detail the design and construction of a speaker using the Bohlender Graebener RD-75 planar magnetic driver. This is the second part of the project, detailing the final part of the speaker construction, measurements and listening trials.

In January 2001, the first audioXPress magazine issue (Vol. 32 No.1) included this project from Thomas Perazella. Published in two parts, the articles described in detail the design and construction of a speaker using the Bohlender Graebener RD-75 planar magnetic driver, including references to previous experiments with dipole baffles. This is the first part of the project.