How Do I Magnetically Shield My Own Speakers? (1 Viewer)

[Ben Chick]

I just bought my first RPTV HDTV-ready Sharp 55" widescreen set. I have set everything up including two large speaker cabinets consisting of a 15" woofer, midrange and tweeter. These speakers are not shielded, but due to room restrictions MUST be placed next to the new TV. I have never had a problem with these speakers in the past next to my 27" Toshiba, but I am suddenly paranoid they could damage my new TV. I have them about 10" away from the set now, but was wondering if I could construct my own video shielding to install in the speaker cabinets. Is this possible? What material would you use? How do I do it?

 

[Huey]

Wrap/hot glue the magnet of driver with thin sheet metal and it should help a lot. Lining cabinet with sheet metal may ruin the sounds. If you open up your shielded speakers, it's the magnet of the driver that's shielded with thin sheet metal. The RPTV is generally less affected than tube TV normally by magnet as the cabinet is larger and keeps the speaker magnets further away than tube TV. You should be able to tell if the speakers adversely affect your new TV by just turning it on and watch for color distortions. If not then you're probably OK. If it does simply move the speakers farther away and no permanent harm is done unless you leave the speakers there for days.

 

[Ben Chick]

Hmm.. sounds good, but where do I buy sheet metal? Maybe a peanut can would suffice?

 

[Kendal Kirk]

Apoxy a 'cancellation magnet' to the back of the drivers magnet with the polarity switched (where the magnets push away from each other). You can get them at http://www.partsexpress.com/pe/pshow...=249-325&DID=7

 

[Guy Kuo]

Most likely you don't need to do anything to the speakers if you are using a RPTV. The case of the TV is quite large and the magnetic field sensitive CRT's are positioned near the center of the TV's bottom portion. Speakers on either side will most likely have minimal effect on the picture. Test it by doing the following.

1. Take your speakers away from the TV. Five feet will be more than enough.

2. Display a convergence grid on the TV. The Crosshatch pattern from AVIA will work fine.

3. Carefully watch the convergence grid for any change in shape or separation of the three colors as you move the speakers back into position.

If you see nothing happen in step 3, your speakers are already far enough away from the internal CRT's to not need shielding. You can relax if that is so and not worry about damaging the TV with the speakers.

However, you can start worrying about how placing your speakers into that position IS damaging the imaging and frequency response of your speakers whether or not they are shielded. Sonic performance will almost always be better if the speakers are well free of obstructions.

 

[Reginald Trent]

How many of the donut magnets should be used per individual speaker? Say you have a 2 way with two 8" speakers and a tweeter? How many per 8" and how many per tweeter?