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 Post subject: Speaker proximity to CRT
PostPosted: Sun Feb 02, 2020 1:42 am 


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Joined: 20 Jan 2019
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Location: Seattle
Is there a consensus on the best way to test how close you can keep your speakers to your CRT?


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sun Feb 02, 2020 1:43 am 


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Test on a light colored background?


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sun Feb 02, 2020 6:57 pm 



Joined: 17 May 2013
Posts: 171
Location: Pennsylvania, USA
In my experience, 24 inches is enough, but I would still be worried about damage over time. If you Google how to magnetically shield a speaker, you’ll see that it doesn’t take much: just a sheet of magnetic metal, like a section from a cookie sheet for instance, can block the interference between the speaker and TV.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sun Feb 02, 2020 9:59 pm 



Joined: 11 Dec 2014
Posts: 379
I wonder about this too. Few years ago I constantly had issues with my CRT and having speakers within 2-3 feet of the TV. I constantly had to turn the TV on and off to degauss it.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Mon Feb 03, 2020 4:02 am 


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I'm working on magnetically shielding my speakers but this seems easier said than done in my initial testing. The problem is that magnets radiate in all directions. So even if you shield the magnet on the back of a speaker and the inside of a cabinet, the magnet still radiates out the front of the speaker.

My only testing right now is with a cheap $2 compass and some tiny neodymium magnets I have.

It just worries me that although shielding may help that it might not protect my BVMs that I want to keep safe for decades to come.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Mon Feb 03, 2020 4:38 am 


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You guys are aware the majority of modern speakers are shielded already right?

Unless you have some massive PA rig next to your TV what are you worried about?

TVs come with internal speakers, all shielded. Think about it.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Mon Feb 03, 2020 3:39 pm 



Joined: 17 May 2013
Posts: 171
Location: Pennsylvania, USA
Syntax wrote:
You guys are aware the majority of modern speakers are shielded already right?

Unless you have some massive PA rig next to your TV what are you worried about?

TVs come with internal speakers, all shielded. Think about it.


This is true in terms of most PC speakers at least. I have a nice set of Andrew Jones pioneers, and only the center channel is shielded. Overtime I would think there is actually less motive for manufacturers to shield their speakers because they are not going to bother a modern display.
Shielding a speaker internally was overkill for me, so I literally *do* use cookie sheets in a way that is not obvious between my CRT and my speakers. I have a Sony Trinitron, hardly a BVM, but there is zero evidence of interference.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Mon Feb 03, 2020 9:08 pm 


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I found manufacturers stopped magnetically shielding home theater speakers years ago when CRT TV's stopped being mainstream.
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 Post subject: Re: Speaker proximity to CRT
PostPosted: Tue Feb 04, 2020 5:22 am 


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I picked up a cheap pair of Black Web speakers from Wal Mart and they caused a warped image on my VGA PC CRT monitor (granted, I had them hugging the display; not much room to work with). Swapped them out for a pair of Logitech speakers and the warping is gone*. Some modern speakers may be shielded, others may not.

*EDIT (two days later): I take that back. I actually fired up the monitor again today with an old PC and the Logitech ones are causing warping as well! Had to move them farther away to get it to go away. If anyone knows of good PC speakers that don't cause interference, I'm all for suggestions.
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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sat Feb 08, 2020 3:56 pm 


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Galgomite wrote:
Syntax wrote:
You guys are aware the majority of modern speakers are shielded already right?

Unless you have some massive PA rig next to your TV what are you worried about?

TVs come with internal speakers, all shielded. Think about it.


This is true in terms of most PC speakers at least. I have a nice set of Andrew Jones pioneers, and only the center channel is shielded. Overtime I would think there is actually less motive for manufacturers to shield their speakers because they are not going to bother a modern display.
Shielding a speaker internally was overkill for me, so I literally *do* use cookie sheets in a way that is not obvious between my CRT and my speakers. I have a Sony Trinitron, hardly a BVM, but there is zero evidence of interference.

There are actually barely any speakers that are shielded these days. The speakers that are shielded are generally models that have been in production for ~20-years.

My B&W CM8 tower speakers that I was attempting to shield were definitely not magnetically shielded and I bought them in 2011. I tried to shield them extensively with multiple layers of shielding material, but it didn't work well enough. My D20 seemed to be fine with it but when I put them next to my D32 the edges of the screen clearly showed discoloring.

With that said, Polk still makes a line of speakers that are magnetically shielded called the RTi series. So I ordered a pair of the Polk RTiA7 tower speakers from Crutchfield last week and I'm happy to report that neither of my CRTs has an issue with these towers being as close as 6"... with that said, I moved them further away just for peace of mind. These speakers are hilariously large towers for my retro game room, but they actually sound great for a $600 pair of speakers and actually don't look too big sitting next to the D32.

Thanks to a fellow community member for the Polk shielded speaker recommendation otherwise I likely never wold have realized that there was still an option for sale.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sat Feb 08, 2020 8:39 pm 



Joined: 22 Oct 2018
Posts: 39
The easiest pair of shielded speakers to pick up at retail these days are the Logitech z623s. I've got them snug bumping right up against my 20L2 with no problems whatsoever.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sun Feb 09, 2020 4:43 am 



Joined: 07 Apr 2016
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Considering that nearly all CRTs have speakers built in and are mere millimeters from the tube, I'm pretty sure that you can place the speakers anywhere as long as they're properly shielded.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Sun Feb 09, 2020 7:22 pm 


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Listai wrote:
The easiest pair of shielded speakers to pick up at retail these days are the Logitech z623s. I've got them snug bumping right up against my 20L2 with no problems whatsoever.

Those are a great recommendation for computer speakers.
I think it gets much harder though to find shielded speakers if/when you look at passive home theater style speakers.

GeneraLight wrote:
Considering that nearly all CRTs have speakers built in and are mere millimeters from the tube, I'm pretty sure that you can place the speakers anywhere as long as they're properly shielded.

I'd imagine that in some cases they've shielded speakers and set the alignment/convergence from the factory to account for the built-in speakers. It's also important to remember that the type of magnet used can play a big role as well as how sensitive the tube is... a small 9" CRT is going to be a lot less sensitive than a 40" CRT.


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 Post subject: Re: Speaker proximity to CRT
PostPosted: Tue Feb 11, 2020 8:50 pm 



Joined: 22 Oct 2018
Posts: 39
Speedy wrote:
Those are a great recommendation for computer speakers.
I think it gets much harder though to find shielded speakers if/when you look at passive home theater style speakers.


Yeah - I should have added that's precisely why I got them. Here in Australia it is especially difficult to find shielded passive speakers so I just gave up because the z623s were more or less good enough for me.


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