Centre Sheilding

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi guys, long time listener first time poster,

Now I'm wondering if it's possible to Shelid a centre speaker by using say +-4mm plate/sheet metal/alloy under the base and ontop?

following config: 0o0

Vifa C13WG | Vifa D26NC | Vifa C13WG

the D26 is a Neo magnet and sheilded but the woofers aren't. The reason i ask is after seeing some pictures of sheilded woofers it looks like it's been surrounded with say 3-4mm metal,

if this isn't possible is there any other way?

and also do non-sheilded driver magnets interfere with your receiver/amp?

thanks in advance, and merry x-mas,

Alex
 
Ex-Moderator
Joined 2002
Hi Alex

Contact Dave (Planet 10) one of our trusty moderators, he had some MU metal available which is the only method of screening drivers, and not totally effectively at that. Beware, however that using sheiding will affect the magnetic field of the driver and may alter its response. If you can buy sheilded versions of the Vifa drivers that would be preferable.
do non-sheilded driver magnets interfere with your receiver/amp
they can to an extent, but not as much as the sound and/or vibration from the speakers, if they are too close.
 
MU Metal? can that be bought in Australia? what is its code i.e. T-6061, i'll message dave.

yes i've heard about it altering the response but after a little googling i read that you can get reverse magnet's? to put onto the driver and a shielding cup over it? are such a devices available at a reasonable price? but i belive it must be match with the same power of the std magnet for it to work

Unfortunatly the vifa dosn't come in a Shielded version as it's a pretty old model now and the aussie supplier is having 50% off on certain models this being one. Being a cheapy bargin hunter i wanna make use of 2 for the price of one,

thanks so far,

Alex
 
Ex-Moderator
Joined 2002
Humm Australia... thats a long way to post lumps of heavy metal...:(

I have never found a supplier of magnets on the web, but someone here may know different! If the drivers are very cheap, you could buy an extra couple and use the magnets from those.

Flown centre system- very rock'n'roll:cool:
 
hehe i'm liking my hovering centre more and more every minute! me thinks i'll string it up on fishing line, hehehe:D look dad a UFH (Unidentified Flying Home theater), lol fishing line it is! would it matter what cable you use? i.e. monofilament fishing line, wire, braided spectra, silk, speaker cable!;)

i'd think i'd need 3 cables to stop her from rock'n'roll'n'

but if there's a way to shield please tell, good idea on buying a few more and using their magnets might do so, their only $24AUS,

cheers,

Alex

hehe, just had another idea, how woul a suspended hometheater go? great for rooms with little space (mine) - not the sub of course:eek:
 
abit off topic but can some tell me if suspending my 4 surrounds and centre (not the sub) on fishing line or wire cable will degrade my sound quality significantly? these speakers are not made yet but the enclosures will look like ice-cream cones and would look pretty smick suspended

I've seen speakers hanging on wire before but only in really big buildings.

Alex
 
Ex-Moderator
Joined 2002
Hi Alex, sorry to take some time to reply but I have been away...

As long as your suspension method can take the weight I personally see no problems with this technique, in fact as you are isolating the speakers it might work quite well.

For suspension, I would use steel cable or chain, as it will have a good safety loading, if for instance, someone decided to have a swing on them:rolleyes:
 
FYI i've just bought 6xC17WG vifa woofers, 5x D25NC tweeters and one M25WO for the sub, which should be here in a few days

have a swing on them

lol:D some people just can't resist. weight isn't an issue as they'll be fixed throuh plaster into support rails

as you are isolating the speakers it might work quite well

i also though the same, plus less cost on me for making stands, the only thing that 'may' happen is the cable singing, from vibrations but i don't see that happening.

I would think that say in space or a space shuttle (weightless environment) sound would be better, but isn't there no air in space? how do communicatrions work in space?

well this is gettin way off topic now, gonna ring round today, see if i can find some MU metal.

here's the type of enclosure i'll be using, designed by andy one of the members here, it will look pretty knarly when suspended!



Click'a'roo Here

merry xmas,

Alex
 
Ex-Moderator
Joined 2002
the only thing that 'may' happen is the cable singing, from vibrations
Unlikely, as Newtons Laws mean the cabinet and driver when regarded as a whole, should stay stationary. But if you do find a problem, you could damp the wires by wrapping cloth around them.

There is no sound transmissions in space as there is no meduim for the to be carried by, so just about every sci-fi movie you ever saw should have completely silent space battles!!! Communication in space is done by radio or lasers, as these emit particles to carry sound. ( apart from the current debate about the accuracy of the Mitchelson & Morley expt, for the physicists amongst us)

The speakers look cool, but gold.... euuuurgh...:)
 
all systems go, where go for launch! hehe:D

an airborn system, does anyone one else have an argument why this may not work, or will be a complete success? any theries on the purpose of a stand and what else it does apart from getting tweeter/enclosure at ear level and looking good?

might get some custom graphis on boxes - *** (Airborn Surround System) lol, this is great,

Alex
 
Love the speakers!

You call that gold though? Looks like copper on my monitor, but that's ok becaue I like copper color better anyhow. :) Gold is just SO old these days, it's used for everything hehe.

Getting back to the shielding question for the center, it's possible you may not need it. Certainly if you suspend the center above the TV you won't, but even in my case, I did not. My center speaker is standing up behind the TV, rather than laying on top of the TV. This means the woofer magnets are then several inches further behind the front baffle of the speaker, and a couple feet above the back of the TV. I also noticed that my TV (Panasonic superflat from 1994) is much less sensitive to magnetic fields in the rear than it is anywhere along the perimeter of the front of the tube. This makes sense - the electron gun is in the rear and the beam has very high strength and intensity when it originates, but is much weaker and thus easier to deflect just before it hits the phosphor on the front.

Anyhow, long story short, if you aren't using super magnet woofers (mine are 6.5", probably 12 oz magnet or so), and your speaker is behind and above the TV, you may not need shielding at all! Usually it doesn't hurt to test. If you get a discoloration on the tube, usually unplugging the set and leaving it unplugged for a while before reconnecting it, will let the discoloration go away. Some TV's even have a degaussing feature which demagnitizes the CRT.

Keep up the cool looking speakers! They're very similar to some I'm putting together this weekend, at least in shape, if not color. My port is going on the front though, not enough room in back!


Aaron Gilbert
 
frugal-phile™
Joined 2001
Paid Member
Alex_B said:
yes i've heard about it altering the response but after a little googling i read that you can get reverse magnet's? to put onto the driver and a shielding cup over it? are such a devices available at a reasonable price?

What you are describing is a bucking magnet. Ideally a magnet of the same strength, placed on the back of the existing magnet -- they should repel as they approach and then when they get close suck together. You glue this on and then to improve it further a can (even a tin can) over everything to help tie the fields togther.

This tends to lower your Qts (by raising the midband efficiency) and is what they do on A/V drivers.

The mumetal acts as a shield, by being very permeable, the flux lines tend to want to follow the metal.

The mumetal foil i have is fairly light, just over $3 to mail 2 12"x6" sheets to Oz.

dave
 
frugal-phile™
Joined 2001
Paid Member
Alex_B said:
is that snail mail where it takes 8wks to get here, or airmail?

It is skinny & light enuff it just goes as 1st class mail which is air. Haven't sent any to Oz but it usually takes 4-7 days to get to Europe. Xmas may or may not slow things down.

DEFINATLY INTERESTED email me about the total cost for 2x 12"x6" sheets, and paymeny options (paypal?). Rather it sent by normal (not express) airmail if it isn't too pricey,

Info is all here

I can take paypal, but not officially. I'll send a mail so we can touch base.

dave
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.