How close dare I place unshielded speakers to my TV?

[kexodusc]

Is there any rule of thumb as to how close you can place unshielded drivers to your tv set?

If it's a trial and error thing, what damage would happen to the tv if I get too close, and is it easily fixed? Anything I should look for as a symptom that my speakers are too close?

[This Guy]

You will see the colors distort on the television. You can actually just move the speaker right next to the TV and see what it looks like...it won't hurt if you just do it for a second or two. Also, many TV's are different. Currently, I have my subwoofer a foot away from the TV and it has a 50oz. magnet and it doesn't affect it at all. On my other TV, it was affected from about 5 ft. from it (cheap GE 19"). It's usually pretty obvious when the magent is affecting it, so If you don't see anything now you should be fine.

[kexodusc]

You will see the colors distort on the television. You can actually just move the speaker right next to the TV and see what it looks like...it won't hurt if you just do it for a second or two. Also, many TV's are different. Currently, I have my subwoofer a foot away from the TV and it has a 50oz. magnet and it doesn't affect it at all. On my other TV, it was affected from about 5 ft. from it (cheap GE 19"). It's usually pretty obvious when the magent is affecting it, so If you don't see anything now you should be fine.

Hmmm, my TV's actually got speakers on either side of the screen, maybe it's self shielded? Okay...if I do screw up the colors, is the damage permanent or will it heal itself?

Geez, I dont' know what I'm so worried about, I use to blast some big Cerwin Vega's back in college next to an old sony tv I had, this was before "magnetically shielded" was buzzword.

[This Guy]

If you move the speaker right neext to it, the colors will be screwed up for a minute or two. Turn it off than on again and it will be gone. The only time it's permanent is if you leave it there for quite some time. I think you're fine.

[kexodusc]

Don't actually have the speakers finished yet, but I'm anticipating building a few more...I'd like to stick with this design instead of moving to shielded drivers which might not be exactly the same...guess I'll just have to test. They'll be about 2-1/2 to 3 ft' away from the screen anyway...thanks This Guy!

[Woochifer]

I guess that would really depend on the TV and the speakers. With my TV, I have my Studio 40s about 1' away, and they don't present any issues at all with the TV. But, if you put the speakers within about six inches, then the image does show color distortions.

[kexodusc]

Yeah, Wooch, my Studio 40's are about 2-3 ft away, I've never had any issues, but aren't they shielded? Or just the Studio CC?

[woodman]

Is there any rule of thumb as to how close you can place unshielded drivers to your tv set?

If it's a trial and error thing, what damage would happen to the tv if I get too close, and is it easily fixed? Anything I should look for as a symptom that my speakers are too close?

Ken:
What type of TV set are you talking about? That makes a world of difference, since RPTVs are [b]not[/b[ subject to the "magnetic problem" that affect direct-view CRT sets. If you ARE talking about a direct-view set, then it indeed is a "trial and error" deal ... no such thing as a "rule of thumb". The effect is a distortion of the color at various places on the screen. As to "damage" to the set: NO, there is not permanent damage of any sort. It can and will be corrected by the de-gaussing circuit that's built into virtually every set today.

But, I must correct a statement made by "ThisGuy" which implied that if you notice such a distortion - just turn the set off and back on again to correct it. This is misleading at best. The de-gauss circuit will only function when the set is turned on from a "cold start" - meaning that it has to have been in an off condition for at least 5 to 10 minutes to allow the de-gauss circuit (primarily the thermistor) to become cool. Then and only then will it do its job.

If the set (direct-view only) has been subjected to a humongous magnetic field, then it may need to be de-gaussed with a professional tool called a de-gaussing coil. But such a situation is rare.

If an RPTV is subjected to such a magnetic field, it could affect the "convergence" by pulling the output of one of the three CRTs away from it's intended path. But this too is quite rare in the real world.

Clear?

[kexodusc]

That's great Woodman, my TV is just a crappy , 3 year old CRT type 36" JVC unit...150 bucks at a police auction, couldn't go wrong!!!

To tell you the truth, if I did fry the TV I might be able to pursuade the fiancee that we need a bigger, newer one...I'm moving to Canada though, until the house is sold money's tight

[risabet]

Is there any rule of thumb as to how close you can place unshielded drivers to your tv set?

If it's a trial and error thing, what damage would happen to the tv if I get too close, and is it easily fixed? Anything I should look for as a symptom that my speakers are too close?

If you can't see any effect than they are far enough away, 1 foot is usually enough, magnetic fields dissiapate rapidly with distance, 2 to 3 feet is better.

[SAPSEC]

This issue had bothered me more than 2 weeks before I decided to buy a pair of BW DM-303
before Christmas (non-shielded). When you see a green or purple circle appeared on tv
then it starts get distorted (ie : hair color changed to green ..) I tried it with my cheap Wega Sony
TV, as long as I can keep them 18 inches away from TV, I don't have any problems.

I later asked BW and JM Lab support and they said the minimum safe distance is to keep
non-shielded speakers 3 feet away (or 90 cm) from your TV screen and this guideline could be
applied to all kinds of speakers and TV screens. Hope this helps !

[woodman]

I later asked BW and JM Lab support and they said the minimum safe distance is to keep
non-shielded speakers 3 feet away (or 90 cm) from your TV screen and this guideline could be applied to all kinds of speakers and TV screens. Hope this helps !

Ahh - the Peter Principle shows up yet again to prove people incompetent at the jobs they are supposed to be competent to perform. This "advice" you were given by people who should know their business (but quite obviously, don't) is wrong from start to finish! There simply is no "minimum safe distance", nor is there any distance at all that is "unsafe". When a speaker causes color distortion on a CRT, there will be NO permanent damage caused. Furthermore, as I already stated in my post above, whether or not a given loudspeaker will cause a "problem" with a TV set, depends on what type of display technology is involved. A speaker that will distort the color badly on a direct-view CRT set, will not affect an RPTV at all - no matter how close it's placed - whether that RPTV is one that is CRT-based, or LCD or DLP-based. Tsk, tsk ... those that dispensed this incorrect "advice" should consider either taking up a different line of work, or else they should actually learn about the business that they're involved with.

[markw]

I've found that sometimes people won't go away unless they are given a simple, definitive answer to a question.

Ya gotta admit, three feet IS a pretty safe answer.

[Sir Terrence the Terrible]

A speaker that will distort the color badly on a direct-view CRT set, will not affect an RPTV at all - no matter how close it's placed - whether that RPTV is one that is CRT-based, or LCD or DLP-based.

Woodman, can you explain to me why when I moved a speaker that is identical to my left/right mains into the center position just in front of my RPTV it began to discolor and distort until I moved it away? I have read where you have said this before, and I was damn confused when I saw distortion on my RPTV.

[woodman]

Woodman, can you explain to me why when I moved a speaker that is identical to my left/right mains into the center position just in front of my RPTV it began to discolor and distort until I moved it away? I have read where you have said this before, and I was damn confused when I saw distortion on my RPTV.

TT:
I'll give it a shot, but first - would you please elaborate and describe your phrase "it began to discolor and distort". Specifics please. Also, what size magnetic structures do these speakers of yours have?

[Sir Terrence the Terrible]

TT:
I'll give it a shot, but first - would you please elaborate and describe your phrase "it began to discolor and distort". Specifics please. Also, what size magnetic structures do these speakers of yours have?

Thanks for your help on this. Well I moved the speaker to just in front of the RPTV, and when I did, the picture started to look like broadcast ghosting. Instead of getting a single S-video prompt from the onscreen display, it looked like three seperate S-video prompts superimposed over one another. It also looked like the convergence was totally off. Once I moved the speaker away, these effects disappear.

The woofer driver on the speaker is a 15", and it weighs about 30lbs. Its a hefty bugger!!

Thanks so much for your help on this, I would REALLY like to use this speaker as my center speaker, but if it is going to mess up the picture, I will keep the one I have, or figure out how to shield the speaker.