Bucking Magnet Size?

[alligatorman]

Hi folks,

I have a recently acquired BIC V62CLR for my HT setup and noticed that it screwed up my TV when placed near it (since it's not video shielded). I did some searching and heard that bucking magnets could be added to reduce the magnetic field...is there a formula to help choose the correct magnet for the drivers and do I have to have one for the tweeter as well?

Thanks
'Gator

 

[mtrycrafts]

Hi folks,

I have a recently acquired BIC V62CLR for my HT setup and noticed that it screwed up my TV when placed near it (since it's not video shielded). I did some searching and heard that bucking magnets could be added to reduce the magnetic field...is there a formula to help choose the correct magnet for the drivers and do I have to have one for the tweeter as well?

Thanks
'Gator

Not sure but I bet you would need the same size and power.
I doubt the tweeter needs one. They are usually small.

 

[---k---]

I've heard about 1/3 of the size of the driver's magnet is good. If you are attaching to the driver, you don't want it to be too heavy, or it could affect the drivers performance. Also, you don't need a 1:1, because the distance will help too. The further away they are, the less the need for the bucking magnets.

They are really cheap and come in several sizes from Parts express. Shipping will likely be more than the magnets themselves. Buy several and experiment.

Another option is to put steel in between the driver and the tv. Some use cookie sheets or whatever. Rolls of steel (avoid aluminium) are avaliable from Home Depot in the roofing supplies area, and that is what I used to line the inside of my subs. Worked real well. I didn't need any of the magnets I bought, even when placing the subs right next to the tv. YMMV due to your tv's sheilding (or lack there-of). You can either try and glue the steel inside your speaker or on the outside just floating.

 

[j_garcia]

Not sure but I bet you would need the same size and power.
I doubt the tweeter needs one. They are usually small.

Not necessarily. The magnets on my tweeters are quite large and they often DO require a shileded version to be placed close to a CRT. Tweeters generally don't use a bucking magnet though, they are usually just encased in steel.

The real solution is not to put them near the TV, as that is generally too close together. If you can't do that, shielding with steel is your next best bet as -k- said, because a bucking magnet needs to be appropriately selected to correctly negate the field of the first magnet without affecting it's performance relative to the voice coil.