Magnet proximity and faceplate shaping - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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
Reply
 
Thread Tools Search this Thread
Old 3rd September 2006, 12:38 PM   #1
kyrie48 is offline kyrie48  United States
diyAudio Member
 
Join Date: Aug 2006
Default Magnet proximity and faceplate shaping

Hello everyone!
Hopefully someone has experience with shaping their own faceplates for custom fits. I've done one set of tweeters, and am planning on doing several other drivers--tweeters and dome mids. My question is: what results have you experienced regarding interference from one magnet to another, etc?
FYI, I use a Black & Decker 'Wizzard' for shaping--using a sanding drum.

Thanks, TTYL
  Reply With Quote
Old 3rd September 2006, 11:41 PM   #2
diyAudio Member
 
Join Date: Mar 2004
Location: Hobart, Tasmania
Send a message via MSN to noodle_snacks
I don't believe having magnets from speakers in close proximity would effect each other a noticeable amount.
  Reply With Quote
Old 4th September 2006, 07:30 AM   #3
Shaun is offline Shaun  South Africa
diyAudio Member
 
Shaun's Avatar
 
Join Date: Aug 2001
Location: Cape Town, South Africa
kyrie48

I don't know the answer to the magnet question, but I hope that noodle_snacks is right, as I'm doing exactly the same as you!

I'm using the RS 28 tweeter and RS D52 mid dome. I've decided that it is best to make the combo face plate in a figure of 8, as this allows one to still use a circle jig to make the cutouts. I'll probably get these professionally made if it doesn't cost too much.
__________________
Shaun Onverwacht
|||||||||| DON'T PANIC ||||||||||
  Reply With Quote
Old 5th September 2006, 05:44 AM   #4
diyAudio Member
 
Join Date: Aug 2006
For added peace of mind in this situation, one could simply use shielded units.
  Reply With Quote
Old 5th September 2006, 09:28 AM   #5
diyAudio Member
 
Larry Lomax's Avatar
 
Join Date: Feb 2005
Location: London Hammersmith
Hello,
By my experience, yes, the flux leeking from the magnet of a loudspeaker influences other loudspeaker nearby. Off course they do. But you don't have to mind about. The influence is so low you'll need good instruments to find out.
Speakers magnets are made to be a nearly closed magnetic circuit excep for the gap where the moving coil moves... So, the flux leaking from outside of the magnetic circuit is only a very little bit of the total.
Another point of view is that magnetic flux from magnets is static, this means no noise nor variation of anything nearby.
An extra point of view, in a speaker, in the middle of the gap in between the two expansion poles, where moving coil moves, there is a very strong magnetic flux flowing and a very strong magnetic field, nothing to share with the very little, small, amount of gouss lost from the outside of other nearby loudspeaker magnets.
Though those disperded magnetic fluxes can chasm your TV screen, or scope's screen, or even collect magnetic dust and iron chips.
Cheers
__________________
Nothing happens by itself, you have to work hard to arrange things to make it happen.
  Reply With Quote
Old 5th September 2006, 01:02 PM   #6
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Traditionally loudspeaker engineers strive to get mids and tweeters together as close as possible for better lobes. They mount coaxial drivers on the back of strong professional woofers like Eminence Beta CX, Tannoy coax etc.
If there was a serious issue with magnets in close proximity, they would have mentioned strongly through the years in papers etc, and we would have seen shielding always and everywhere right from the first 2 way loudspeaker. So no issue apparently.
  Reply With Quote
Old 5th September 2006, 01:46 PM   #7
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
slightly off topic but related.

Why is the backplate on a ferrite magnet smaller than the face of the magnet?

Would the flux going around the magnetic circuit have an easier job if the whole magnet face had a backplate to transfer the magnetic field to the pole piece?
__________________
regards Andrew T.
  Reply With Quote
Old 6th September 2006, 05:41 AM   #8
kyrie48 is offline kyrie48  United States
diyAudio Member
 
Join Date: Aug 2006
Thanks for all the replies, now I have "peace of mind" with respect to future projects... don't have to worry about defeating my efforts by causing more problems than solving!
(Of all I've read about design, I never came across any mention of this concern... but there are several similars, as you all know)

Thanks one and all!!
TTYL
  Reply With Quote
Old 6th September 2006, 02:14 PM   #9
diyAudio Member
 
Larry Lomax's Avatar
 
Join Date: Feb 2005
Location: London Hammersmith
Quote:
Originally posted by AndrewT
Hi,
slightly off topic but related.

Why is the backplate on a ferrite magnet smaller than the face of the magnet?

Would the flux going around the magnetic circuit have an easier job if the whole magnet face had a backplate to transfer the magnetic field to the pole piece?
Well, this is a good question...
I've seen this in many loudspeakers, as I've seen full backplates on many others...

I'd like to know too...
__________________
Nothing happens by itself, you have to work hard to arrange things to make it happen.
  Reply With Quote
Old 6th September 2006, 04:11 PM   #10
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
It cannot be to save weight and cost.
They are penny pinchers but there must be a technical reason.
__________________
regards Andrew T.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Onkyo VLSC Vector Linear Shaping Circuitry rjm Digital Source 4 18th October 2011 11:10 AM
magnet design 101 - saturate iron with a ferrite magnet? capslock Multi-Way 18 28th April 2010 04:51 AM
Box-tuning magnet-to-magnet construction Mr_Oasis Full Range 21 2nd June 2009 12:51 AM
speaker magnet proximity Question pango Tubes / Valves 2 21st August 2007 06:38 AM
Nth order noise shaping sovadk Class D 21 21st February 2005 06:55 AM


New To Site? Need Help?

All times are GMT. The time now is 07:53 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2