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The Saga of One Lansing 500A Monitor System

Above is an old black and white picture of the then new Los Angeles Manual Arts High School. How does this relate to the Lansing Heritage? A fair question, and one with an answer I would never have believed would involve me personally. But I'm getting ahead of myself.


LMCo Monitor System 500 Bulletin 3
Altec Lansing Technologies, Courtesy Dr. Bruce Edgar

In the fall of 1999, I received a packet of photocopies from another vintage audio hobbyist. Included among several assorted old speaker catalogs were about twenty pages of Lansing Manufacturing Company sales literature, circa 1937. I knew this was James Lansing's first business and I was therefore amazed and delighted. I had always held little hope of ever finding literature from this obscure firm. Among the fascinating sheets were bulletins described the Lansing Shearer Horn and Iconic. However, one bulletin had special interest to me. It was labeled "Bulletin #3" (shown to the left) and described the new Lansing Monitor System. Pictured on top was an illustration of a premier installation - the Los Angeles Manual Arts High School.

I knew of this place from a friend whose business occasionally takes him to the school. I asked him if he would check out the auditorium on his next visit, just on the remote chance that there was a trace of the old Lansing system. He called me a few days later to report that he had been by to have a look. He had observed a grill cloth covered alcove over center stage, which looked as though it may have been constructed to inconspicuously house a loudspeaker. As no enclosure or wires were visible, he concluded that any original speaker had probably been removed long ago.

After I related this story to another friend, he visited the school to double check the auditorium. He too could not see any evidence of a speaker, until he shined a flashlight on the grille cloth in front. He was barely able to detect the glint of a multicellular horn! We discussed alternatives for trying to acquire this system, but there didn't appear to be an easy solution. Even if its purchase could be arranged with the school, the removal of this 240 pound enclosure from its high perch would be a daunting task. We decided to put aside any thoughts of acquisition for the time being

During our investigations, someone at the school had mentioned that the auditorium was scheduled for major remodeling. Recently, my friend with the flashlight revisited the school and noticed that workers were busily removing items from the auditorium's interior - the remodeling had begun. Checking inside, he observed that the speaker alcove had been taken down. When asked about the speaker, a worker replied "We threw it away two weeks ago". When pressed, he indicated that it might still be in the debris pile out back. My friend spotted the enclosure in the rubble, and was given permission to remove it. He loaded it into his pickup trick, drove home and gave me a call. This circa 1937 Lansing system now resides in my workshop. I am thrilled to have this historically significant loudspeaker.


Monitor System 500 Enclosure
Steve Schell

As one can see from from the picture at right, it is indeed a Lansing Monitor System - a Model 500A to be precise. It had been hung from the roof by three steel ropes in an inverted configuration, with the high frequency horn on the bottom. The elaborate rigging included four long 7/16" diameter bolts running through the enclosure, with double nuts and support plates to insure structural integrity. The enclosure had been modified, rather crudely, to allow the high frequency horn to angle down more sharply than the box as a whole. This may possibly have occurred at the time of the original installation. The original model 15XS bass driver, crossover network and field supply had been removed at some point, and a pair of inexpensive 12" permanent magnet woofers installed over crudely cut holes in the rear of the enclosure. These woofers had recently been appropriated by students at the school for a science project. The original 805 multicellular horn and 284 compression driver were still in place.


805 Horn
Steve Schell

The 805 horn, undoubtedly the earliest version to bear this designation, is fascinating to examine closely. It is somewhat smaller than the later Altec tar filled and B series versions. There are other differences as well. In the Lansing version, the individual cells are terminated flush with the throat mounting flange, and are carefully filed to knife-like edges. The outer four cells are actually curved slightly near the throat to facilitate this arrangement. The throat adapter incorporates a 2-1/2", 16 thread-per-inch coupling, to mate with the model 284 and 285 drivers of the day. It is also interesting to observe that the individual cell edges fit closely together at the mouth, without the "spacers" employed in the later horns. This requires that the cells, especially the outer ones, distort somewhat from a square cross section. Additionally, the Lansing horn was not painted, and the original metal has a smooth patina, in contrast to the mottled appearance of the galvanized steel apparently used in the later Altec horns.


284 Driver
Steve Schell

The compression driver used in this system is the model 284 that was a legacy of the Shearer Horn project. The driver has a 2.84" aluminum diaphragm and edgewound coil. It is energized by a field coil using eight pounds of copper wire. The phase plug uses three annular slits as opposed to the radial slit 285. The throat exit is 1.5" in diameter and connects to the 805 horn by means of a threaded coupling

The enclosure was originally painted a light yellow color, possibly to match the auditorium's interior. The front had been repainted a royal blue, and the front and rear later resprayed a bubblegum pink color, 805 horn and all. One wonders whether the enclosure may have been visible in the auditorium in the early years, and concealed later by the alcove and grille cloth.

Current plans are to repair the 12" woofer holes and restore the loudspeaker, insofar as possible, to original performance. A Lansing 15XS woofer, in dire need of reconing, is on hand and may find it's way into the enclosure. A new dividing network and field supply, in keeping with the originals, will have to be built. It would be gratifying to restore this fascinating and historical piece of sound equipment to useful service.

2000 Steve Schell