User Name Posted December 4, 2003 Share Posted December 4, 2003 I have a KLFC7 center channel sitting on top of my big screen. The other day I noticed a rainbow prism in the center of the screen shining up toward the KLFC7. It's only noticable when you stand up directly in front of the screen looking over down the front of it. At normal viewing level and angle it's totally unoticeable. I imagine this is not good for the TV and was wondering what my methods should be to rectify it? Should I place a piece of plywood under the speaker? The magnet is obviously strong enough to get through the speaker box. Do you think it'll go through another 3/4" piece of plywood? It would look cheesy/tacky on top of the TV but maybe if I painted it black or something it'd be better. Have any of you run across this before and what did you do? Thank you. 1 Quote Link to comment Share on other sites More sharing options...
mbajner Posted December 4, 2003 Share Posted December 4, 2003 the C7 is shielded and is supposed to not cause problems near a TV. but, this is a large speaker. try a shelf a few inches above the TV. this might just do the trick. for experiment, use books at first to see how much space is required. I have a RPTV and the C7 sits right in front of the set on a stand. no problems at all. Quote Link to comment Share on other sites More sharing options...
dougdrake Posted December 4, 2003 Share Posted December 4, 2003 Wonder if the rainbow you are seeing is just the protective screen refracting light rather than the magnet of the speaker actually doing anything. Usually magnetic interference looks like a blob of a single color or two, rather than a rainbow, I believe. dd Quote Link to comment Share on other sites More sharing options...
ironwoods Posted December 4, 2003 Share Posted December 4, 2003 I was also under the impression that an RPTV is less prone to interferance, because the video coils(?) are located at the bottom/rear of the enclosure. Maybe turn off the amplifier when your standing in the suspect position. Quote Link to comment Share on other sites More sharing options...
User Name Posted December 6, 2003 Author Share Posted December 6, 2003 When I take the speaker away and fix the convergence on the TV, it goes away so I know it's not the screen. 1 Quote Link to comment Share on other sites More sharing options...
User Name Posted December 6, 2003 Author Share Posted December 6, 2003 Turning off the amp has nothing to with my problem. The amp doesn't even have to be on. The speaker isn't even on. Just the unpowered unused speaker's magnet alone distorts the screen. It's weird. I have feet on the speaker protruding roughly 3 inches but obviously that's still not tall enough to retard the shielding. 1 Quote Link to comment Share on other sites More sharing options...
minn_male42 Posted December 6, 2003 Share Posted December 6, 2003 take the drivers out of the cabinent and see if the bucking magnets are still in place on the speaker magnets.... there should be a metal can type of enclosure on the back of each woofer.... Quote Link to comment Share on other sites More sharing options...
MasterT Posted December 7, 2003 Share Posted December 7, 2003 I had the same problem with my RC-35. I have a tube TV and from what I understand they are very sensitive to magnetic fields. I had to put mine on a shelf on the wall behind the TV. It sucks but I had no alternative. I have been told that putting a sheet of copper between the TV and the speaker may help, but I have not tried it. Could you elaborate more on "bucking magnets". I have heard of this. Changes the magnetic field or something. Are all Klipsch center channels equipped with these? Quote Link to comment Share on other sites More sharing options...
minn_male42 Posted December 7, 2003 Share Posted December 7, 2003 the bucking magnets are glued to the back of the speakers magnet in opposite polarity.... this cancels out the magnetic field so you don't get the distortion on your tv... if you have older klipsch speakers and want to place them close to your tv, you can order bucking magnets directly from klipsch.... just tell them what speakers you have.... Quote Link to comment Share on other sites More sharing options...
User Name Posted March 9, 2004 Author Share Posted March 9, 2004 I prefer not to open the backs of the speaker. It's pretty solid and I'd hate to ruin them. Here's an idea, Does klipsch make longer feet? I suppose I could hit a hardware store and manufacture some feet out of a long screw but I'm not sure I could match the threading or the color (black). Does anyone know if they sell replacement spikes? maybe some 6 or 8 inchers will do. 1 Quote Link to comment Share on other sites More sharing options...
M6 Driver Posted March 10, 2004 Share Posted March 10, 2004 "I prefer not to open the backs of the speaker" Negative! you'll gain access to the magnets by removing the drivers from the front of the C7. If you wanted to get in through the back just give it to UPS for a couple of hours. Quote Link to comment Share on other sites More sharing options...
rckpls Posted March 10, 2004 Share Posted March 10, 2004 A KLF-C7 sits on top of my 50" Toshiba without any problems, and I don't think the speaker magnet can cause the problem you are describing with a rear-projection TV. Is is possible the weight of your speaker is causing the top of your TV to bow, thereby bending or distorting the screen? Quote Link to comment Share on other sites More sharing options...
Cleve Posted March 13, 2004 Share Posted March 13, 2004 That's strange. One of my CF-4's with two big 12" woofers sits about 8" from the side of my 1994 Zenith television - and there's absolutely no magnetic effect so it must be shielded. This TV seemed sensitive to magnetic interference too - My old Pinnacles used to affect it if placed too close. The KLF's were produced a year or two later, so I can't imagine them not being shielded, with the rapid growth in home theater and all. And my RC-25 sits atop this same tv - and there's no magnetic interference whatsoever. I do occasionally get a blob of color on the side of my TV adjacent to the cabinet where my amplifier resides. I've found that turning the TV on and off degausses the screen. Quote Link to comment Share on other sites More sharing options...
HornEd Posted March 13, 2004 Share Posted March 13, 2004 I have banished my two KLF-C7's to Front Effects Speaker duties on either side of the right and left KLF-30 mains. But when I did use them atop a 65" Mitsubishi RPTV, there was no interference from the C7. Now I have a "HORNizontalizED" KLF-30 atop the Mitsubishi without any distortion problems whatsoever. However, if I allow any of the front array KLF-30's to be closer to the sweet spot than the big Mitsu screen is... instant "rainbows" appear. Just my two C7 cents worth. -HornEd Quote Link to comment Share on other sites More sharing options...
Cleve Posted March 15, 2004 Share Posted March 15, 2004 HornEd, this is probably a stupid question, but would magnetism have any effect on a projection TV, shielded or not? There's no tube for magnetic fields to distort(?) Also, how did you mount the KLF-30 for center channel duty? I'm considering buying another pair of CF-4's so I can use one as a center channel for the true 'perfect match' for my front CF-4's. Since the KLF-30 and CF-4 are fairly similar in size and weight, I'm curious how you've set it up. Thanks! Jim Quote Link to comment Share on other sites More sharing options...
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