Jump to content

LCD Displays and magnets


Recommended Posts

Chinhda is developing a custom sub-frame for a client. The concept is a self-contained module with all the essential components in one box that could be affixed to a cart or used independently. Monitors will be mounted in the doors seen in the photos here. We want a latch that would hold the doors securely closed but, because of the need to fit the whole business within a standard Pelican case, there is very little extra room to fit additional hardware.

Using a magnet to hold the doors closed is an obvious solution. But, we've hesitated because the magnets would be so close - an inch or less - to the monitors. These are LCD monitors so my research and my experience tell me that we ought to be OK, that magnets distort and harm cathode monitors but not LCD. Still the magnets would be a permanent part of the LCD monitor environment.

What is the experience of the group on this question?

Thanks.

David

Link to comment
Share on other sites

Eric's got the right idea --- no need to do a lot of technical research, just hold a magnet (probably one like the ones Chinhda might be using) up to some small LCD monitors, large LCD monitors, etc. The video monitors should be powered up I imagine and run the magnet all over the case, on the screen, etc., and observe if there appears to be anything happening to the picture. This is not scientific of course and also does not tell you anything about potential long term damage by magnetic fields and other theoretically potential nonsense, but I think it would help you make some decisions.

Link to comment
Share on other sites

Long term exposure to a CAT scan or MRI sized magnet will damage your LCD screen. The screen in my friends laptop who works as tech support (or something like that) for MRI machines, is all purple on one side and audibly whistles. Not sure how big a magnet you'll be using, but interesting nonetheless.

Link to comment
Share on other sites

Yes, I intend to make just that kind of test. But I was also concerned about long term consequences and thought others in the group might have applicable knowledge.

David

If the magnets in the speakers in the picture haven't affected the tv in 6 years then I doubt the little ones you mentioned will do any damage. I run 2 sets of speakers next to the tv, the small self powered AudioTechnica MMS 557 and the 6' tall Maganapans powered by a 275wpc Carver power amp.

Eric

post-22-0-43443000-1326254274.jpg

Link to comment
Share on other sites

If the magnets in the speakers in the picture haven't affected the tv in 6 years then I doubt the little ones you mentioned will do any damage. I run 2 sets of speakers next to the tv, the small self powered AudioTechnica MMS 557 and the 6' tall Magnepans powered by a 275wpc Carver power amp.

Eric

Wow, I learn something new everyday about Eric... Magnepans, wow.

Link to comment
Share on other sites

Wow, I learn something new everyday about Eric... Magnepans, wow.

No, WOW!! is the dual voice coil 12" 150wpc self powered sub woofer on the floor behind the tv and the two bookshelf JBL speakers with a 10" dual voice coil 100wpc sub woofer for the rear channels. I can get the lights to dim in tempo when I turn them all up. :blink:

and to my friend Vin, indeed I do remember your help with the tv & the cabinet.

Eric

Link to comment
Share on other sites

Eric, you have a separate sub for the surrounds? Did I read that right?

Indeed you did. Because sometimes I use the surrounds as the main system when I just want to listen and not LISTEN. Here's a picture of the rear surround speakers. The rear sub woofer is under the table in the corner. The little mouse looking thing on the table at the base of the lamp is the remote I made to turn on and control the level of the small speakers nearest the tv and yes they have their own seperate woofer also.

Eric

post-22-0-46058300-1326291378.jpg

Link to comment
Share on other sites

Gentlemen,

Thank you for your responses. I have run a magnet around the perimeter of my LCD monitors and can see no image degradation at all. I have one attached to the housing now (obviously some steel in there somewhere) to see if anything develops. So far, so good.

The magnets Chinhda uses to keep drawers and panels closed are surprisingly strong. They snap out of your hand if brought anywhere near metal - it's almost like the comic magnet effect one might see in a Maxwell Smart episode. They are much stronger than the magnets customarily used by furniture manufacturers in cabinet doors, etc. but, then, furniture isn't usually bounced along trails or uneven sidewalks.

Still they are not the intense magnets one would use in an MRI machine. I have some familiarity with that because Susan, my wife, worked for awhile in research in Nuclear Magnetic Resonance Spectroscopy. They used a super-conducting magnet for best performance; it needed liquid helium to keep it sufficiently cold and that whole business was surrounded by a dewar filled with liquid nitrogen to keep the helium from boiling off. One had to remove one's watch before entering the magnet room.

Eric, that is one impressive system. I remember auditioning Magneplanars when I was purchasing a home system; they were wonderful but beyond my budget at the time. (probably still beyond it)

David

Link to comment
Share on other sites

Eric, that is one impressive system. I remember auditioning Magneplanars when I was purchasing a home system; they were wonderful but beyond my budget at the time. (probably still beyond it)

David

My Maggie's are 32 years old and were about $1700 a set back then. They are still $1700 today except that would be for one speaker now.

Eric

Link to comment
Share on other sites

Magnepan offers a new speaker model using the same unique technology as used in the 37 year old speakers Eric has. They call the new speaker the MMG and you can purchase a pair for $599.00. They liken these smaller less expensive speakers to the "tasters" handed out in supermarkets, designed to give you a taste of the full product (the larger and more expensive speakers). From the Magnepan website:

"Of course, the larger Magneplanars models will outperform the 'appetizer' MMG model, but, Magnepan makes the claim that it is the technology that is fundamentally different from your box speakers. And that difference in sound reproduction can be 'tasted' with a small version of their large models. With a hint of humor, Magnepan 'warns' consumers that if you try the MMG, you run the risk of new speakers in your future."

post-1-0-88963500-1326299453.jpg

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...