Jensen G-610 triaxial loudspeaker data
I have played both violin and viola in symphony orchestras for many years, and being an electronics engineer in my
day job, the combination has generally dictated more than a passing interest in audio equipment. In the continuing
search for sound that most closely approximates that which I hear in the concert hall, I built a pair of 250lb Jensen
plywood horns several decades ago (one of these refrigerator sized behemoths is shown below.) These enclosures were
intended by the Jensen engineers to be a no-compromise roll-around version of their 'prettied up' living room "Imperial" product,
primarily for use in recording studios and sound labs. There is obviously nothing attractive about them...heh.
At the same time, I have yet to find their equal in reproducing the orchestral program material that I listen to
most of the time.
Ever since building them, I've been collecting data on the G-610 and G-600 reproducers intended to inhabit these
plywood monsters. Unfortunately, I have found a dearth of such data on the web, so I thought it might be helpful
for the occasional searcher to put all of these in one place, listed below. Their antecedents are long gone, so I
apologize in advance if I have included anything without credit where it is due. I'll gladly give credit if the
original provider will send me a note at the e-mail address shown in the link at the bottom of this page.
Jensen Technical Bulletin No. 1 (March 1952)   "A Back-loading Folded Horn for
15 Inch Loudspeakers" - the construction details for the uncompromised Imperial enclosure above.
Jensen Technical Bulletin No. 3 (July 1952)   "Construction of Back-loading
Folded Horn Cabinets for 12 and 15 Inch Loudspeakers" - a smaller cabinet design that requires the cabinet to be placed in a corner, similar
to the Klipsch design.
Jensen Technical Bulletin No. 4 (December 1952)   "The Reproducer of the Future" -
basically an Imperial cabinet set sideways on top of an eight foot long transmission line loaded subwoofer, which covers the bottom octave below 45 Hz.
Jensen Instruction Note 133 (undated, but probably ca. 1951 because there is no mention of the
1952 effort on the Hypex flare horn designs)   "The Jensen G-610 Triaxial Loudspeaker" - covers the technical details of the
G-610 and G-610A design with the A-221 crossover network. This model differs from the later G-610B design in a couple of areas, primarily the crossover.
Jensen Instruction Note 133B (also undated, but probably ca. 1960, coincident with the G-610B introduction)
"Jensen G-610B Triaxial Loudspeaker" - covers the technical details of the
G-610B design with the A-640 crossover network.
Plach-Williams paper covering the technical details of the Imperial horn enclosure
"Horn Loaded Loudspeakers"    A very readable article on some of the tradeoffs that influenced the design of the Imperial horn,
including an overall response curve of its performance.
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