Does a 2441 affect a CRT Television?

[Don McRitchie]

It is the physical design. The alnico magnet is placed in the center of the VC and the return casting completes the circuit. I doubt that Mr. Lansing cared about shielding, but rather wanted to design the most efficient motor with as little flux loss as possible.

I tend to agree, but it is interesting that even the 1945 JSMPE article by Jim Lansing on his new Altec 604 design describes one of that speaker's benefits being its shielding when used with CRT's. Since this was before the widespread consumer adoption of TV, I'm guessing it was in reference to military CRT devices like radar displays. Altec was a major military electronics contractor at the time.

[edgewound]

I just tried a little experiment a minute ago. I held a 2420 (not 2441)alnico driver next to my Philips 17" CRT computer monitor and noticed the following: The most stray flux field radiates from the loading cap side of the driver, and it's alot. you can actually see the flux field in the CRT screen when held infront of the glass. The stray field looks to be signifcantly less when the 2420 is rotated 90 degrees, but still enough to mess with the color....so I'm sure the 2440/41 would cause much more disturbance to the screen. You could fabricate a Mu-metal case to shield the driver..do a Google search for Mu-metal.

So..the alnico drivers do have enough stray field when VERY close to the CRT to upset the color/picture...even when off to the side or top/bottom

[paragon]

A distance of 6-8 " at the side (monitor) is enough.