[Bob]

I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above the
54" HDTV. Thanks

[Eeyore]

Bob wrote:

I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding.

Forget it and use a shielded driver.

Graham

[Trevor Wilson]

"Bob" wrote in message
...
I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

**A 'bucking' magnet, of approximately the same magnetic force. Apply it to
the existing magnet. Then, cover the whole magnetic assembly with some soft
iron or, preferably, mu metal. Better still, follow Graham's advice.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[John Stone]

On 12/15/06 9:52 PM, in article , "Bob"
wrote:

I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above the
54" HDTV. Thanks

Just curious. What kind of 54" HDTV uses a CRT?

[dizzy]

John Stone wrote:

On 12/15/06 9:52 PM, in article , "Bob"
wrote:

I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above the
54" HDTV. Thanks

Just curious. What kind of 54" HDTV uses a CRT?

Would have to be a rear projector, which means it probably won't be
affected by external speakers since the CRT's are in the middle, a
couple feet from the sides of the cabinet.

[dizzy]

Trevor Wilson wrote:

"Bob" wrote in message
...
I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

**A 'bucking' magnet, of approximately the same magnetic force. Apply it to
the existing magnet. Then, cover the whole magnetic assembly with some soft
iron or, preferably, mu metal. Better still, follow Graham's advice.

That's some really bizarre advice. Would it not be easier to shield
it with some mu-metal?

[AZ Nomad]

On Fri, 15 Dec 2006 22:52:56 -0500, Bob wrote:


I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above the
54" HDTV. Thanks

If it a 54" TV, then it isn't a direct view CRT. It'll be a projection system
and the tubes will be on the bottom of the case. If you put the center speaker
on top, you shouldn't need shielding for any speaker smaller than 7" or so.

[Bob]

"John Stone" wrote in message
...
On 12/15/06 9:52 PM, in article , "Bob"
wrote:

I am planning to build a centre channel speaker box using the same type
of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

Just curious. What kind of 54" HDTV uses a CRT?

It is a Panasonic PT53X54 rear projection. Sorry, I was out 1 inch as the
size is 53".
I am sensing shielding is a non-issue due to the distance from the CC to the
TV centre?

[ScottW]

"dizzy" wrote in message
...
John Stone wrote:

On 12/15/06 9:52 PM, in article , "Bob"
wrote:

I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above the
54" HDTV. Thanks

Just curious. What kind of 54" HDTV uses a CRT?

Would have to be a rear projector, which means it probably won't be
affected by external speakers since the CRT's are in the middle, a
couple feet from the sides of the cabinet.

Yup...My 65" Mitsu is surrounded by unshielded speakers
including some massive magnet woofers to no ill effect.
I doubt this little CC will have any effect.
Minor shift can be compensated
if the TV has a decent convergence control.

ScottW

[John Stone]

On 12/16/06 11:33 AM, in article ,
"dizzy" wrote:

Trevor Wilson wrote:

"Bob" wrote in message
...
I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

**A 'bucking' magnet, of approximately the same magnetic force. Apply it to
the existing magnet. Then, cover the whole magnetic assembly with some soft
iron or, preferably, mu metal. Better still, follow Graham's advice.

That's some really bizarre advice. Would it not be easier to shield
it with some mu-metal?

You would normally use a magnet slightly smaller than the main one and then
a shielding cup over the whole magnet assembly. If you just use a bucking
magnet, you will effectively cancel the field to the sides but you'll
actually increase the stray field to the rear. Depending on the drivers in
question, aftermarket shielding kits are available.

[AZ Nomad]

On Sat, 16 Dec 2006 13:14:34 -0500, Bob wrote:



"John Stone" wrote in message
...
On 12/15/06 9:52 PM, in article , "Bob"
wrote:

I am planning to build a centre channel speaker box using the same type
of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

Just curious. What kind of 54" HDTV uses a CRT?

It is a Panasonic PT53X54 rear projection. Sorry, I was out 1 inch as the
size is 53".
I am sensing shielding is a non-issue due to the distance from the CC to the
TV centre?


The screen's center is irrelevent. What matters is the distance between the
nearest speaker and CRTs which are probably near the bottom of the case.

[Trevor Wilson]

"dizzy" wrote in message
...
Trevor Wilson wrote:

"Bob" wrote in message
...
I am planning to build a centre channel speaker box using the same type
of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

**A 'bucking' magnet, of approximately the same magnetic force. Apply it
to
the existing magnet. Then, cover the whole magnetic assembly with some
soft
iron or, preferably, mu metal. Better still, follow Graham's advice.

That's some really bizarre advice.

**Nothing bizarre about it. It is standard practice.

Would it not be easier to shield
it with some mu-metal?

**Nope. A bucking magnet is most helpful. Try and find some mu-metal. After
you do, try to form it into the required shape, without destroying it's
properties. All in all, it is a dumb idea.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[dizzy]

Trevor Wilson wrote:

"dizzy" wrote:

Would it not be easier to shield
it with some mu-metal?

**Nope. A bucking magnet is most helpful. Try and find some mu-metal. After
you do, try to form it into the required shape, without destroying it's
properties. All in all, it is a dumb idea.

Would it not suffice to just put a slab of it on the side of the
speaker (or the TV)? Not the most aesthetically pleasing solution, I
realize, but if the speaker is right next to the TV it may not matter.

[Trevor Wilson]

"dizzy" wrote in message
...
Trevor Wilson wrote:

"dizzy" wrote:

Would it not be easier to shield
it with some mu-metal?

**Nope. A bucking magnet is most helpful. Try and find some mu-metal.
After
you do, try to form it into the required shape, without destroying it's
properties. All in all, it is a dumb idea.

Would it not suffice to just put a slab of it on the side of the
speaker (or the TV)? Not the most aesthetically pleasing solution, I
realize, but if the speaker is right next to the TV it may not matter.

**Nope. Like almost all forms of interference, the solution should be
applied at the source.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

[Eeyore]

dizzy wrote:

Trevor Wilson wrote:

"Bob" wrote in message

I am planning to build a centre channel speaker box using the same type of
single woofer/tweeter drivers as the surrounds. Was wondering what is
required in the way of shielding. The CC would be sitting about 6" above
the
54" HDTV. Thanks

**A 'bucking' magnet, of approximately the same magnetic force. Apply it to
the existing magnet. Then, cover the whole magnetic assembly with some soft
iron or, preferably, mu metal. Better still, follow Graham's advice.

That's some really bizarre advice. Would it not be easier to shield
it with some mu-metal?

Have you seen the price of mu-metal ?

If you bend it, the magnetic properties get f***ked anyway.

Proper shielded drivers are designed with a different style of magnetic circuit.
Better to address the problem at source rather than try to fix it.

Graham