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Re: Double loaders...

Posted by Steve Schell (M) on February 7, 2007 at 09:50:44

In Reply to: Re: Double loaders... posted by Paul Eizik on February 6, 2007 at 21:12:50:

Hi Paul,

RCA did build a compound horn system for small theatre use in the late 1930s which closely resembled Figures 1,2,3. I've never seen one of these rarities in person, and don't know if the front horn actually contained the resonating chamber(s). Seems like a hip idea though to keep the front horn from honking below its cutoff, since there was no electrical crossover to limit low frequencies being fed to the driver.

The partial obstructions of the rear horn shown as #29 in Figure 9 are described in Olson's text as being embodied by 1) the reduction in cross section from chamber 27 to the beginning of the horn sections 19a and 19b, and 2) the reduction of cross section at 21 where the horn path travels through panel 11.

RCA built the design shown in Figures 5,6,7 as the 64A Monitor (late 1930s) and 64B Monitor (mid 1940s). The two models differed in external styling but seem to be the same internally. I have a pair of the 64Bs, and (not having studied the patent carefully) have been puzzled by the restrictions to the rear horn path. As built, the first obstruction is actually much more severe than indicated in the patent. A crosswise panel at the rear of chamber 27 leaves only a vertical slit barely wide enough to admit fingers at the point where the path splits in two. Perhaps this was an example of Olson's cleverness as you indicated, describing the function well enough for the patent but not tipping the competition as to the actual embodiment. The second obstruction is similar to the patent drawing, perhaps just a bit more severe than shown.

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