Lessen the magnetism?

Hi. Maybe a strange info request, but I need to know if there is something that I can either coat the interior/exterior of my enclosure with that will either lessen or contain the magnetism from the sub magnets or something I can layer or whatever.

I had 3 solabaric 12in L5s in a custom partial fb enclosure. My fiance recently got a pacemaker and whenever she'd ride with me the magnets were so strong that they would cause interference with her pacemaker.

I'm in the process of cutting down the box to accommodate 2 12in L5s. But I sure would hate to be wasting my time and havta go to one or worse, havta get rid of them entirely. That's why I was wondering if there is anything as far as coating or layering to ensure no more intereference.

Thanks in advance,

okay.....I don't understand all the properties of a magnet and how its field effects the subwoofer performance, but that aside....

How far apart? (if I was to somehow place another equal magnet)

Will it not effect the performance of the sub?

Thanks sparky,

sparkie wrote:

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If you place another magnet equal to the origninal one behind the speakers magnet, it will reduce the magnetic field in size.

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muzique800
.           You'll have to find a way to contain the field. There are various ways to do this, but being that you are using a FG enclosure, you'll need to be geometrically creative or be willing to put out a small pretty penny for the proper shielding.

Creative: Get a stainless steel sheet (or if you have the resources, iron sheet) and wrap it around the sub's magnet structure. Leave at least 1.5 inches of space around the magnet structure, or else it will distort the field and reduce the abilities of the sub. If the sub is facing the passengers, then you'll have to place a shield in front of the sub as well... Holes and cutouts (for designs/whatever) are fine so long as the cutout holes are no larger than 1" across and/or the cutouts/holes take no more than 20% of the area to be covered out. Double layers with 1 cm space between layers will really cut it down.

Pretty Penny: CuPro-Cote Paint. It'll cost about $150 for 1 quart ($30 for 4 oz, but that doesn't lay a good coat even for small enclosures), and it doesn't freeze well, but it's legit. You'll need to lay a few thick coats on the inside of the enclosure for it to work well. We found while dealing with this stuff that if you have an HVLP gun, spraying it lightly on the back of the cone (if you have access to it) or to the front will help reduce the magnetic field.

If you can be both creative and don't mind spending the penny, do both. You'll have near 0 magnetic field escape from the enclosure. There will be some magnetic fielding radiating from it, but it should be cut down about 80-95% depending how thick the CuPro is and how well your sheets are shielding.

Good Luck and our best regards to you and your fiance

Thanks so much for your input bellsracer.

I'll prolly go with the paint. Yes, I have a paint gun. Was wondering about resonance thru the sub. Sounds like spraying the back of the cone is a good idea, but does that not interfere/change performance?

Have you heard of or have any experience with MagnetShield? I found this product just before I read your reply.

I've searched and searched with no results, pertaining to subs interfering with pacemakers or defibrillators. Guess most people with one are too old to appreciate a good bump, huh? ha ha

Thanks again,

With all due respect, you're talking about how to reduce interference to your fiance's ***P_A_C_E_M_A_K_E_R***!!!!!  As in, the pacemaker that helps keep her heart in rhythm... Don't take any chances. Talk to the doctors. If they say that they don't recommend her sitting in there with the subs, TAKE THEM OUT!. What's more important to you?

From what I've read, 6 inches is typically the distance recommended to keep stuff away from the pacemaker/defib unit. Some of these devices have magnetic switches inside them to allow external manipulation of the action of the unit.. placing a magnet on the skin above the device is done to put the unit into baseline or troubleshooting mode. Having said all that, I can assure you that I don't know enough about them to comment on what might or might not be safe for them.. please, also consider the possibility of the sound pressure waves affecting the operation of the unit, not just the magnetics.

I'm not meaning to be an *sshole or anything, I'm just looking for a reality check.

Jim

Well said mad scientist. I didn't want to be the first to ask where priorities were set. I'd give up stereos altogether if it was a health issue for my family. Sorry muzique800 I just don't see the point in risking her life. My only suggestion is get a project car to custimize and have your stereo in. That way you can have the best of both worlds a fiance and a booming stereo. 

Check it out, I totally agree with Mad Scientists that if it truly messes with the pacemaker take them out.  But something you can try is a sheet of lead.  Lead is what the put over you to protect against radiation or whatever when you get x-rays, also a lady at my office sat on the other side of a huge battery backup system at my office, it was in the LAN room, her monitor on the other side of the brick wall was jumping like a fan was on next to it.  What they did to fix that and to cut down on the magnetic interference caused by the massive amounts of electricity on the otherside of the wall was to install a lead plate or sheet of lead.  I don't know if it works with magnets but I believe that's what's shielding speakers for center channels for home audio.  So if it's that important to you to have subs, then I would look into the lead sheets.  Hope that helps.

CaFociGuy, Micah

Now I really feel retarded now... I guess I got so into the solution I completely forgot about the safety >.< Sorry

Listen to the Mad Scientist! MS is good, MS is wise.

Thanx everyone, for your input. And yes, Mad Scientist is right. That was my first suggestion to my fiance.... to just take them out completely. However, she insists that I TRY to find a way to keep the boooom in the truck.

I spoke with her cardiologist and he doesn't understand why there is even an issue. I think it was mostly the setup of the subs. Relative to her proximity to the top sub magnet. I've been so busy lately that I haven't worked on the box in many weeks. All that's left, is to do whatever it is I'm going to do to help the shielding, put the top on, mount the connection terminal, re-cover it, and of course insert and hookup the subs.

 Here's what it WAS like before I started chopping.

I'll check back later and maybe add the new finished pic, and tell you guys what I ended up doing.

Thanx,

J

:: sigh ::

This isn't something to be taken lightly... I am not sure how sensitive the pacemakers are to magnetic fields, but all I can see left for a POSSIBLE solution would be to make a blow-through system with metal cone subs that have a relatively low draw. The key for this to keep the boom would be making a really well tuned box... I would contact someone with really good tuning software and build from there...

Beyond this, there isn't much more you can really do except some cutting and loading larger speakers. 8" square subs in a ported box could potentially bring some boom without building a large field. Try and find as sensitive speakers as you can to maximize output and minimize the field. cutting in 6x9s to assist in the boom will help with building big sound with the subs. Combine them with the paint, and you shouldn't have much of an issue with fields.

To help boost sound even further, use sealed-foam baffles on all the speakers. Recommend getting them from Crutchfield... They're fairly inexpensive but provide a lot of isolation to help "boost" sound; well, rather keep from destroying sound within the panels.

To minimize skinning effect, probably best to run the power wires on the passenger side and the signal wires on the driver's side.

Here I go again with going nuts with the design. But I guess it is ok with the hopes that it is to bring sound safely to everyone no matter their status.

I guess the key here would be smaller magnet's with higher sensitivity and proper isolation and control of sound. I wonder if a 6x9 can be ported as well >.<