Magnetic fields and CRT TVs

[cameronthorne]

I've heard Thomas say that the effects of a nearby unshielded midrange on a CRT television depend entirely on how far away it is from the TV, and how well shielded the TV itself is.

Is it possible to test out the TV set itself without having a built speaker? How strong of a regular magnet should I wave around to represent the normal magnetic field from an unshielded midrange driver? I have a few midrange drivers sitting around, but no way currently to pump a signal into them.

It's a Sony KD-30XS955 by the way.

-- Cameron

[Kevin P]

It's not the signal going into the speaker that causes issues with CRTs, it's the driver's magnet itself.

Therefore, you can test without having a built speaker, by gradually moving the driver(s) toward the TV and see if you get any distortion. Avoid getting too close to the screen since if you magnetize the shadow mask you could end up with a splotch that won't go away without degaussing.

[cameronthorne]

Sweet. I'll try it out when I get home tonight. I assume having something like a white background displayed on the screen would allow me to see the color shift the easiest?

-- Cameron

[ThomasW]

You won't need any special screen background. The magnet will distort the colors of any standard TV program

[---k---]

Also note, someone here recently got in trouble with the center channel crossover. Just moving the crossover to the top of the box solved the problem.

I don't think you're going to find that you need a ton of room.

And, if you do put the speaker too close to the screen too many times, and get a perminate distorted spot, try turning your tv on and off about 15 - 20 times. Most newer tvs will do a minor degauss each time you turn it on and off. Eventually, it will fix the problem. At least it did for me after I experimented with my RL-p15 driver and the TV.

[digital desire]

Actually, I had to 'remote' the crossover (center channel speaker -wm/tw). The crossover now lives on the floor in its own little cabinet.
It was really only a problem that I noticed during dvd concerts that had a strong center presence.