These are my main speakers, and I have eight in total. In 2007, I replaced the drivers with Atlas-Soundolier C10AT82 units. The original Dukane 5A527 speakers and transformers are also shown (for the record: there is absolutely nothing wrong with the originals—except sound quality—and they would likely continue to operate for the rest of my lifetime). Also shown is a pair of mounting brackets and a screw, after an inside view of the bracket mounted to a loose box. That funny shadow on the grille cloth of this particular box is chalk (I think—no idea how it got there). Someday, I might just put some padding on the parallel walls in these things.
Also note that these Dukane speakers are somewhat wider than most surface-mount American PA speakers. Not only does this give a little more volume (which forces the speakers to have a bit more mid-bass response), it also makes them look somewhat like the typical Japanese school speakers. Too bad these are dripping in tacky 1970s styling (they were actually made in 1977, and the 6A560 below was made in 1980, according to the date-stamps on the original drivers). The “woodgrain” finish is actually printed vinyl and the grille “cloth” is also some kind of woven plastic.
The 6A560 is just a 6A557 cabinet with an attenuator potentiometer added. I only have one of these. The original driver is the black 5A525. You’ll notice the blue relay—that’s the “volume override” circuit that I added.
I got a reasonably good deal on a dozen “new in box” Atlas C10AT87 speakers. They come in half-dozen boxes, as shown above. I believe they were made circa-2000. About the same time, I also found a dozen new HT82 transformers (also come six to a box). So I replaced the HT87 transformers to make the C10AT82 sets that I actually wanted.
The HT82 and HT87 transformers have similar specs, except they are made for a 25v and 70v line, respectively. This model is third up from the bottom—compare to the tiny Dukane units (which are the equivalent of the lowest model). Larger transformers generally have a wider frequency response range, so these sound noticeably better than the original Dukane units.
The two lowest models of 8-inch drivers made by Atlas are the C5A and C10A (the number indicating the weight of the ceramic magnet in ounces). I also have a couple C5A units, and they are basically the same as those original Dukane speakers (except with a whizzer cone rather than the tacky shiny dome). The speakers themselves don’t really sound that different—how and where you mount them, and the transformer, makes a much larger difference.
Note that the frequency-response and all such data on the Atlas components can be found on the official spec sheets, which are available somewhere on the company website. Except the Chinese-made HT87 transformers, I believe that all of the Atlas components shown above are American-made.