Merideth,

I have something like that set up and it seems much stronger than my old
setup.  I have speaker magnets on the outside facing into the coil in a
repelling format from both ends of coil.  On the center pole I situated a
neo and on the neo is a steel bolt fitting the inside of the coil.  The
opposing bolts therefore are repelling inside the coil and the speaker
magnets provide a large attracting opposite field larger in diameter than
the coil.  I find it actually better not to push the poles to far into the
coil but to allow the field to exit through more of the coil length.  I
suppose if the neo magnets actually fit inside the coil I would gain more.

Randy
----- Original Message ----- 
From: 
To: 
Sent: Tuesday, June 03, 2008 02:00
Subject: Digest from 06/02/2008 00:00:21


>
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 1                                                           |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Pondering 2 stacked ring magnets = round coils
> From:    "meredith lamb" 
> Date:    Mon, 2 Jun 2008 10:00:57 -0600
>
> ------=_Part_19632_5839218.1212422457930
> Content-Type: text/plain; charset=ISO-8859-1
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> Hi all,
>
> Hmmm, here is a new/old speaker/voice coil speculation idea, which I don't
> think has been covered before in PSN email.
>
> It "assumes" you have a round coil that does reasonably fit the inside
> diameter of a, and/or, a pair of round ring neodymium magnets;
> and; ~ the total thickness of the neodymium magnets is at least greater
than
> the thickness of  the coil itself.
>
> You take 2 round ring magnets and simply co-join them N-S-N-S.  The field
> where they co-join (S-N) will be quite
> intense, and is where the movement of the coil will be most sensitive.
This
> is the only real change/addition.
>
> The old voice coil or speaker magnet setups usually have a centered iron
> vertical rod straight up through the
> center, and had the normal base plate to which it was attached.  Something
> similar would be nice to have but
> probably not too difficult to "add on" or home brew to the stacked pair of
> ring magnets.  I suppose a "base plate" of just
> a larger size iron washer could serve to begin with, but probably a square
> steel plate with a centered/mounted iron bolt
> or whatever could be fashioned to enhance the overall sensitivity to
seismic
> movement.
>
> I don't really know, but I would think the coil output sensitivity could
> exceed that of a single ring neodymium magnet
> by perhaps ~ 2x over that of a single ring magnet; and (?) perhaps many
> times that of the old single alnico "U" magnet.
>
> In reality...the old round coils will be with us forever....this setup
> "might" work a heck of alot better....
>
> Meredith Lamb
>
> ------=_Part_19632_5839218.1212422457930
> Content-Type: text/html; charset=ISO-8859-1
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> Hi all,

Hmmm, here is a new/old speaker/voice coil speculation
idea, which I don't think has been covered before in PSN
email.

It "assumes" you have a round coil that does
reasonably fit the inside diameter of a, and/or, a pair of round ring
neodymium magnets;

> and; ~ the total thickness of the neodymium magnets is at least greater
than the thickness of  the coil itself.

You take 2 round ring
magnets and simply co-join them N-S-N-S.  The field where they co-join
(S-N) will be quite

> intense, and is where the movement of the coil will be most
sensitive.  This is the only real change/addition.

The old voice
coil or speaker magnet setups usually have a centered iron vertical rod
straight up through the

> center, and had the normal base plate to which it was attached. 
Something similar would be nice to have but
probably not too difficult to
"add on" or home brew to the stacked pair of ring magnets.  I
suppose a "base plate" of just

> a larger size iron washer could serve to begin with, but probably a square
steel plate with a centered/mounted iron bolt
or whatever could be
fashioned to enhance the overall sensitivity to seismic movement. 

I
don't really know, but I would think the coil output sensitivity could
exceed that of a single ring neodymium magnet

> by perhaps ~ 2x over that of a single ring magnet; and (?) perhaps many
times that of the old single alnico "U" magnet.

In
reality...the old round coils will be with us forever....this setup
"might" work a heck of alot better....

> 
Meredith Lamb

 



>
> ------=_Part_19632_5839218.1212422457930--
>
>
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 2                                                           |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Re: Pondering 2 stacked ring magnets = round coils
> From:    Brett Nordgren 
> Date:    Mon, 02 Jun 2008 12:44:35 -0400
>
> Meredith,
>
> Would it possibly work better if the ring magnets were oriented N-S - S-N?
>
> Regards,
> Brett
>
> At 10:00 AM 6/2/2008 -0600, you wrote:
> >Hi all,
> >
> >Hmmm, here is a new/old speaker/voice coil speculation idea, which I
don't
> >think has been covered before in PSN email.
> >
> >It "assumes" you have a round coil that does reasonably fit the inside
> >diameter of a, and/or, a pair of round ring neodymium magnets;
> >and; ~ the total thickness of the neodymium magnets is at least greater
> >than the thickness of  the coil itself.
> >
> >You take 2 round ring magnets and simply co-join them N-S-N-S.  The field
> >where they co-join (S-N) will be quite
> >intense, and is where the movement of the coil will be most
> >sensitive.  This is the only real change/addition.
>
>
>
>
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 3                                                           |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Re: Pondering 2 stacked ring magnets = round coils
> From:    "meredith lamb" 
> Date:    Mon, 2 Jun 2008 12:13:34 -0600
>
> ------=_Part_20429_20515475.1212430415011
> Content-Type: text/plain; charset=ISO-8859-1
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> Hi Brett,
>
> Interesting thought Brett!
>
> Of course co-joining S to S, is a real (like near impossible) mechanical
> "bear" with same pole/s repulsion.   One could mentally
> intertain the though of using a non-magnetic spacer inbetween (probably at
> least 1/4" thick) to greatly ease up on the mechanical
> magnet containment support, AND, here is where one would absolutely need a
> centered bolt to get the necessary N pole attraction
> and coil induction.  I'd think it could possibly provide a more throughly
> uniform field more totally through the coil yes.  Such a
> arrangement might allow using the thinner ring magnets (like cheaper) for
> use.  The use of a non-magnetic spacer will
> seem to give much more vertical latitude for seismometer drift problems
> also.
>
> Mentally if one goes further with possibilities, "if the coil, had high
> enough length; it could also work "without"
> the center bolt; as then the flux can pass through the top/bottom N pole
> fields.  Here also, the thought of multiple
> same size coils stacked, "might" provide sensor induction and or perhaps
> some limited mass damping fine tuning.
>
> Take care, Meredith Lamb
>
> On Mon, Jun 2, 2008 at 10:44 AM, Brett Nordgren 
> wrote:
>
> > Meredith,
> >
> > Would it possibly work better if the ring magnets were oriented N-S -
S-N?
> >
> > Regards,
> > Brett
> >
> > At 10:00 AM 6/2/2008 -0600, you wrote:
> >
> >> Hi all,
> >>
> >> Hmmm, here is a new/old speaker/voice coil speculation idea, which I
don't
> >> think has been covered before in PSN email.
> >>
> >> It "assumes" you have a round coil that does reasonably fit the inside
> >> diameter of a, and/or, a pair of round ring neodymium magnets;
> >> and; ~ the total thickness of the neodymium magnets is at least greater
> >> than the thickness of  the coil itself.
> >>
> >> You take 2 round ring magnets and simply co-join them N-S-N-S.  The
field
> >> where they co-join (S-N) will be quite
> >> intense, and is where the movement of the coil will be most sensitive.
> >>  This is the only real change/addition.
> >>
> >
> >
> > __________________________________________________________
> >
> > Public Seismic Network Mailing List (PSN-L)
> >
> > To leave this list email PSN-L-REQUEST@.............. with the body of
the
> > message (first line only): unsubscribe
> > See http://www.seismicnet.com/maillist.html for more information.
> >
>
> ------=_Part_20429_20515475.1212430415011
> Content-Type: text/html; charset=ISO-8859-1
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> Hi Brett,

Interesting thought Brett!

Of course co-joining S
to S, is a real (like near impossible) mechanical "bear" with same
pole/s repulsion.   One could mentally
intertain the though of
using a non-magnetic spacer inbetween  (probably at least 1/4" thick)
to greatly ease up on the mechanical

> magnet containment support, AND, here is where one would absolutely need a
centered bolt to get the necessary N pole attraction
and coil
induction.  I'd think it could possibly provide a more throughly
uniform field more totally through the coil yes.  Such a

> arrangement might allow using the thinner ring magnets (like cheaper) for
use.  The use of a non-magnetic spacer will
seem to give much more
vertical latitude for seismometer drift problems also.

Mentally if
one goes further with possibilities, "if the coil, had high enough
length; it could also work "without"

> the center bolt; as then the flux can pass through the top/bottom N pole
fields.  Here also, the thought of multiple
same size coils stacked,
"might" provide sensor induction and or perhaps some limited mass
damping fine tuning.

> 
Take care, Meredith Lamb

On Mon, Jun
2, 2008 at 10:44 AM, Brett Nordgren <Brett3mr@.............>
wrote:

> Meredith,

> 

> Would it possibly work better if the ring magnets were oriented N-S -
S-N?

> 

> Regards,

> Brett


> 

> At 10:00 AM 6/2/2008 -0600, you wrote:

> 

> Hi all,

> 

> Hmmm, here is a new/old speaker/voice coil speculation idea, which I
don't think has been covered before in PSN email.

> 

> It "assumes" you have a round coil that does reasonably fit the
inside diameter of a, and/or, a pair of round ring neodymium magnets;

> and; ~ the total thickness of the neodymium magnets is at least greater
than the thickness of  the coil itself.

> 

> You take 2 round ring magnets and simply co-join them N-S-N-S.  The
field where they co-join (S-N) will be quite

> intense, and is where the movement of the coil will be most sensitive.
 This is the only real change/addition.

> 
> 

> 

> __________________________________________________________

> 

> Public Seismic Network Mailing List (PSN-L)

> 

> To leave this list email PSN-L-REQUEST@.............. with the body of the
message (first line only): unsubscribe

> See http://www.seismicnet.com/maillist.html for more
information.

> 


>
> ------=_Part_20429_20515475.1212430415011--
>
>
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 4                                                           |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Re: Pondering 2 stacked ring magnets = round coils
> From:    ChrisAtUpw@.......
> Date:    Mon, 2 Jun 2008 19:52:40 EDT
>
>
> --part1_cee.35e4b90d.3575e1c8_boundary
> Content-Type: text/plain; charset="US-ASCII"
> Content-Transfer-Encoding: 7bit
>
> In a message dated 2008/06/02, paleoartifact@......... writes:
>
> > Hmmm, here is a new/old speaker/voice coil speculation idea, which I
don't
> > think has been covered before in PSN email.
>
> Hi Meredith,
>
>        I can't follow the construction proposed from your description. Can
> you make a sketch, please?
>        Are the ring Neo magnets magnetised along their length?
>
>        Regards,
>
>        Chris
>
> --part1_cee.35e4b90d.3575e1c8_boundary
> Content-Type: text/html; charset="US-ASCII"
> Content-Transfer-Encoding: quoted-printable
>
> In a
me=
> ssage dated 2008/06/02, paleoartifact@......... writes:

> 

> 
 : 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">Hmmm, here is a new/old
speaker=
> /voice coil speculation idea, which I don't think has been covered before
in=
>  PSN email.


> 

> Hi Meredith,

> 

>        I can't follow the construction
propose=
> d from your description. Can you make a sketch, please?

>        Are the ring Neo magnets magnetised
alo=
> ng their length?

> 

>        Regards,

> 

>        Chris   
>
> --part1_cee.35e4b90d.3575e1c8_boundary--
>
>
> .------ ------ ------ ------ ------ ------ ------ ------ ------ ------.
> | Message 5                                                           |
> '------ ------ ------ ------ ------ ------ ------ ------ ------ ------'
> Subject: Re: Pondering 2 stacked ring magnets = round coils
> From:    "meredith lamb" 
> Date:    Mon, 2 Jun 2008 19:10:25 -0600
>
> ------=_Part_22051_14203881.1212455425553
> Content-Type: text/plain; charset=ISO-8859-1
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> Hi Chris,
>
> Sorry; I do see MY lateral text description error.  The 2 ring mags are
> common in that they are polarized
> through the thickness, not the ring outer diameter, with the usual
Internal
> Diameter hole.  Each N - S represents
> the poles of a single magnet, and they (the letters) are of course much
> wider than the thickness.  The center
> mag holes would be vertical per this view and are not seen.  They are not
> diametrically magnetized (sideways
> through the outer ring diameter....hmmmm....which might be also
> interesting....ha.  Of course any coil/s would
> drop down the center of this "stack".  Below is a stack of 2 ring magnets:
>
> N
> -
> S
> N
> -
> S
>
> What Brett proposed is:
>
> N
> -
> S
> S
> -
> N
>
> What might be mechanically more practical is to insert a non-magnetic
> spacer, shown below with the letter "O".
>
> N
> -
> S
> O
> S
> -
> N
> Wish I had some large ring neo mags on hand to try it out and whomp up a
> simple web photo page; but alas;
> no; for the moment.  Of course its hard to match common round coils with
the
> internal diameter of ring magnets
> to where their is some space for movement versus....too much space (too
> small a coil for the mag ID).  They
> might be interesting to check out...but...one can't adjust much here.
>
> Of course, just using 4 square/rectangular neo's within 2 plates of iron
> metal, gives quite excellent sensitivity with
> using round coils.  Indeed; for dampening curiosity, I tried such
recently,
> and with the coil leads shorted, it had
> quite a very pronounced eddy current drag, I've never seen before with
other
> magnet arrangements for the specific
> 2k resistance coil I used as a test coil.
>
> Take care, Meredith
>
> On Mon, Jun 2, 2008 at 5:52 PM,  wrote:
>
> > In a message dated 2008/06/02, paleoartifact@......... writes:
> >
> > Hmmm, here is a new/old speaker/voice coil speculation idea, which I
don't
> > think has been covered before in PSN email.
> >
> >
> >
> > Hi Meredith,
> >
> >        I can't follow the construction proposed from your description.
Can
> > you make a sketch, please?
> >        Are the ring Neo magnets magnetised along their length?
> >
> >        Regards,
> >
> >        Chris
>
> ------=_Part_22051_14203881.1212455425553
> Content-Type: text/html; charset=ISO-8859-1
> Content-Transfer-Encoding: 7bit
> Content-Disposition: inline
>
> 
Hi Chris,
> 
 
> 
Sorry; I do see MY lateral text description error.  The 2
ring mags are common in that they are polarized
> 
through the thickness, not the ring outer diameter, with the usual
Internal Diameter hole.  Each N - S represents
> 
the poles of a single magnet, and they (the letters) are of course
much wider than the thickness.  The center
> 
mag holes would be vertical per this view and are not seen.
 They are not diametrically magnetized (sideways
> 
through the outer ring diameter....hmmmm....which might be also
interesting....ha.  Of course any coil/s would
> 
drop down the center of this "stack".  Below is a
stack of 2 ring magnets:
> 
 
> 
N
> 
-
> 
S
> 
N
> 
-
> 
S
> 
 
> 
What Brett proposed is:
> 
 
> 
N
-
> 
S  
> 
S
> 
-
> 
N
> 
 
> 
What might be mechanically more practical is to insert a
non-magnetic spacer, shown below with the letter "O".
> 
 
> 
N
> 
-
> 
S
> 
O
> 
S
> 
-
> 
N

> 
Wish I had some large ring neo mags on hand to try it out and whomp
up a simple web photo page; but alas;
> 
no; for the moment.  Of course its hard to match common round
coils with the internal diameter of ring magnets
> 
to where their is some space for movement versus....too much space
(too small a coil for the mag ID).  They
> 
might be interesting to check out...but...one can't adjust much
here.
> 
 
> 
Of course, just using 4 square/rectangular neo's
within 2 plates of iron metal, gives quite excellent sensitivity
with
> 
using round coils.  Indeed; for dampening curiosity, I
tried such recently, and with the coil leads shorted, it had
> 
quite a very pronounced eddy current drag, I've never seen before
with other magnet arrangements for the specific
> 
2k resistance coil I used as a test coil.
> 
 
> 
Take care, Meredith  
> 
 
> 
On Mon, Jun 2, 2008 at 5:52 PM, <ChrisAtUpw@.......> wrote:

> 

> 
In a message dated 2008/06/02, paleoartifact@......... writes:


> 
Hmmm, here is a new/old
speaker/voice coil speculation idea, which I don't think has been
covered before in PSN email.
> 

Hi Meredith,

       I
can't follow the construction proposed from your description. Can you
make a sketch, please?
       Are the ring
Neo magnets magnetised along their
length?

       Regards,

> 
       Chris


>
> ------=_Part_22051_14203881.1212455425553--
>
>
> __________________________________________________________
>
> Public Seismic Network Mailing List (PSN-L)
>
> To leave this list email PSN-L-DIGEST-REQUEST@.............. with
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