AR driver makers ?

[Guest Droog]

In an earlier post, CTS is noted as a maker of the woofer for the 4x and the midrange for the 2ax. Who

was CTS ? Who else made drivers for AR in the 1960s (2 & 2ax woofer, 3 & 3a woofer, dome tweeters)?

Off topic; While at a junk yard in Rowley, MA last year looking for parts for my '63 Rambler I noticed a

early 60s Ford panel van with 'AR Inc.' painted on the sides. It must have been some sort of company van.

( unfortunatly no speakers of parts left inside!)

[tysontom]

>In an earlier post, CTS is noted as a maker of the woofer

>for the 4x and the midrange for the 2ax. Who

>was CTS ? Who else made drivers for AR in the 1960s (2 &

>2ax woofer, 3 & 3a woofer, dome tweeters)?

> Off topic; While at a junk yard in Rowley, MA last year

>looking for parts for my '63 Rambler I noticed a

>early 60s Ford panel van with 'AR Inc.' painted on the sides.

>It must have been some sort of company van.

>( unfortunatly no speakers of parts left inside!)

CTS was a well-known OEM manufacturer of component drivers, such as woofers, midranges and tweeters. Some were off-the-shelf, others were custom-manufactured to manufacturing spec. AR contracted with CTS of Paduka for the 3-1/2-inch AR-4x/AR-2ax driver, and specifically a CTS engineer-type by the name of Charles "Chuck" McShane worked on these drivers for AR, then later was hired from 1965 to 1975 by AR under Roy Allison. McShane went on to help in the design of several key AR speakers such as the AR-3a. for the 3-1/2-inch midrange replacement in the AR-2ax. This driver was heavily modified and treated to meet AR's specs for flat frequency response, even at the expense of high-end extension.

The AR-4 also used this custom-made CTS 3-1/2-inch driver as its midrange/tweeter, but the AR-4x's 2-1/2-inch midrange/tweeter was designed and built in-house at AR, of course by Roy Allison and Chuck McShane. Both of these drivers are really quite excellent, both about equal through the midrange, which was perfect for the AR-2ax. The 2-1/2-inch driver in the AR-4x was much superior in the treble and in off-axis response.

The AR-2 and AR-2a, incidentally, used two 5-inch midrange drivers that were also made by Carbonneau, another OEM driver manufacturer. These inexpensive 5-inch drivers were extensively treated with fiberglass under the cones and liquid latex on the cone edge, and the result was a driver capable of very uniform midrange output up to about 13-15 KHz.

The woofers for all AR speakers were largely made in-house. Of course, speaker frames, cones and such were out-sourced, but coil winding, assembly, testing and so forth were done in the AR plants. All of the dome tweeters except for the first version of the AR-14 1-inch dome tweeter were made in-house at AR. The first AR-14 dome was a peerless unit, but later ones were made by AR, so-to-speak.

AR used panel trucks and pickup trucks to run back and forth between plants down at 24 Thorndike Street in Cambridge, Massachusetts. AR occupied buildings on both sides of the street, and it was necessary to move equipment, raw materials and finished goods back and forth. That truck was probably one of the units used for that purpose.

--Tom Tyson

[soundminded]

CTS also manufactured the 4 inch drivers used in Bose 901 for their original version and for Series II. They were apparantly segregated by Bose into three groups so that if you needed a replacement driver, they would have to determine which group your particular unit used. By Series III, Bose had built their own in house units and had abandoned their acoustic suspension design and wood enclosure for a ported design with an injection molded plastic enclosure.

[Guest Sean]

The original Bose 901's used nine 8 ohm drivers wired in a parallel-series circuit to achieve a nominal 8 ohm circuit. The later versions used nine 1 ohm drivers wired in series to obtain the same nominal 8 ohm impedance. Sean

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