Bucking Magnets - Need Iinfo

mp006ltk · 13th March 2008, 02:43 PM

Hi I haven't been able to find out alot in books on the subject. I know that the use of a bucking magnet will increase Bl and sensativity, but what's the tradeoff? You usually don't get anything for free. What is the downside to doing this? Thanks!

Lsharptec1 · 13th March 2008, 03:03 PM

mp006ltk,

The primary purpose of using a bucking magnet is magnet field cancellation. It is an alternative to wrapping the speaker magnet in a mu metal shield.

I am not aware of any adverse effects.

Larry

mp006ltk · 13th March 2008, 08:21 PM

yeah i know they can be used to semi shield a driver, but I'm more interested in the effect on the performance.

Cal Weldon · 13th March 2008, 08:49 PM

I don't believe there is one. Not even sensitivity as far as I know.

EDIT: I would think the only way for it to affect performance would be to add it in the same direction as the driver magnet rather than mounting it as a bucking magnet which is flipped over and glued. Still I'm not sure that it would change much if anything.

sreten · 13th March 2008, 09:03 PM

Hi,

Its like having a slightly larger magnet, so really only a downside
if the magnet is already too large, but still not much real difference,
you've got the wrong driver in the first place.

/sreten.

P.S. bucking magnets are a prerequisite of fitting screening cans.

sreten · 13th March 2008, 09:06 PM

Quote:

Originally posted by Cal Weldon
I don't believe there is one. Not even sensitivity as far as I know.

Hi, BL up by 10% and sensitivity up 0.65dB, Seas MCA12,

/sreten.

Cal Weldon · 13th March 2008, 09:32 PM

Thanks for that sreten. Good to know. Was that with a magnet the same size as the original and was it attached in the same direction or bucking?

sreten · 14th March 2008, 02:43 PM

Hi,

Same direction ? I cannot see any point of doing that.

What the bucking magnet does is force the stray field behind the
driver to flow through the front stray field and the magnetic circuit,
or more exactly not allow the rear stray field field flux paths.

Its a small gain for a massive magnet compared to including the
extra magnet in the magnetic circuit. Would be far cheaper to
use a slightly larger magnet.

/sreten.

13th March 2008, 02:43 PM	#1
mp006ltk diyAudio Member Join Date: Oct 2004	Bucking Magnets - Need Iinfo Hi I haven't been able to find out alot in books on the subject. I know that the use of a bucking magnet will increase Bl and sensativity, but what's the tradeoff? You usually don't get anything for free. What is the downside to doing this? Thanks!

13th March 2008, 08:21 PM	#3
mp006ltk diyAudio Member Join Date: Oct 2004	RE: yeah i know they can be used to semi shield a driver, but I'm more interested in the effect on the performance.

13th March 2008, 08:49 PM	#4
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	I don't believe there is one. Not even sensitivity as far as I know. EDIT: I would think the only way for it to affect performance would be to add it in the same direction as the driver magnet rather than mounting it as a bucking magnet which is flipped over and glued. Still I'm not sure that it would change much if anything. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

13th March 2008, 09:32 PM	#7
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	Thanks for that sreten. Good to know. Was that with a magnet the same size as the original and was it attached in the same direction or bucking? __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

13th March 2008, 03:03 PM	#2
Lsharptec1 diyAudio Member Join Date: Oct 2004	mp006ltk, The primary purpose of using a bucking magnet is magnet field cancellation. It is an alternative to wrapping the speaker magnet in a mu metal shield. I am not aware of any adverse effects. Larry

13th March 2008, 09:03 PM	#5
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Its like having a slightly larger magnet, so really only a downside if the magnet is already too large, but still not much real difference, you've got the wrong driver in the first place. /sreten. P.S. bucking magnets are a prerequisite of fitting screening cans.

14th March 2008, 02:43 PM	#8
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Same direction ? I cannot see any point of doing that. What the bucking magnet does is force the stray field behind the driver to flow through the front stray field and the magnetic circuit, or more exactly not allow the rear stray field field flux paths. Its a small gain for a massive magnet compared to including the extra magnet in the magnetic circuit. Would be far cheaper to use a slightly larger magnet. /sreten.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Adding a bucking magnet, what effects does it have	pjpoes	Multi-Way	2	9th November 2008 05:49 PM
Changing the Q of FR125S with Bucking Magnets	xfmrengr	Full Range	3	16th February 2007 11:56 AM
bucking magnet ?	woody	Multi-Way	2	14th October 2002 03:51 AM
Bucking magnet question	woody	Everything Else	1	1st June 2002 07:55 AM
Bucking Magnets	markkanof	Multi-Way	3	23rd January 2002 02:32 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read