magnetic poles of a speaker motor

Clipped · 15th January 2009, 02:30 PM

can a speaker operate if the voice coil interacts with only one pole of the magnet?

Vaughan · 15th January 2009, 06:30 PM

Wouldn't that mean that the cone only moves in one direction ? I mean both north and south poles are required for both positive and negative wave cycles (and polarity changes based on the AC wave cycle or how far along the wave cycle is)

So then I take it that the waveform wouldn't be reproduced. But I'm sure someone more knowledgeable will tear my words down.

Regards,

ABJensen · 15th January 2009, 07:09 PM

No a magnet always have two poles.So the the voicecoil will interact with both.

Clipped · 16th January 2009, 01:25 AM

you only need 1 pole for the voice coil to move.

HK26147 · 16th January 2009, 01:34 AM

you answered your own question.
Audio is AC and does the change of attraction/repulsion in the voice coil.

Clipped · 16th January 2009, 10:04 AM

just wanted to double check before i drop $200 on NEO bars to make a sub.

Steerpike · 16th January 2009, 10:19 PM

Quote:

No a magnet always have two poles.So the the voicecoil will interact with both.

Exactly so.

But you may be planning to have the coil only near one pole; the other pole far away - which in effect give you a really HUMONGOUS air gap, compared to conventional driver construction.
Result = low magnetic flux = poor effieciency & low power handling.

HK26147 · 16th January 2009, 11:15 PM

There are a variety of transducers that use only 1 pole of a bar magnet such as the ribbon tweeter on this page:
http://www.lautsprechershop.de/hifi/aka_hoch_en.htm
http://www.visaton.com/bilder/sonsti...utsprecher.gif
Audio Magazine had a construction article ( 70's ) orienting neo bars magnets in V's on both sides of the membrane.

Perhaps an unconventional design is in mind?

15th January 2009, 02:30 PM	#1
Clipped diyAudio Member Join Date: Mar 2005 Location: home	magnetic poles of a speaker motor can a speaker operate if the voice coil interacts with only one pole of the magnet?

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

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Jensen 4-poles capacitors for sale	hc167	Swap Meet	3	19th September 2008 07:32 PM
Transfer function. Poles not where expected	Raka	Multi-Way	35	29th July 2008 01:20 PM
correct # of poles source selector?	h_a	Solid State	2	6th February 2007 09:28 AM
Bypasses still needed w/ Jensen 4 Poles?	tonyptony	Parts	1	10th April 2006 03:54 PM
Bypasses still needed w/ Jensen 4 Poles?	tonyptony	Power Supplies	0	9th April 2006 07:41 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


	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

15th January 2009, 06:30 PM	#2
Vaughan diyAudio Member Join Date: Jan 2004	Wouldn't that mean that the cone only moves in one direction ? I mean both north and south poles are required for both positive and negative wave cycles (and polarity changes based on the AC wave cycle or how far along the wave cycle is) So then I take it that the waveform wouldn't be reproduced. But I'm sure someone more knowledgeable will tear my words down. Regards,

15th January 2009, 07:09 PM	#3
ABJensen diyAudio Member Join Date: Mar 2005 Location: copenhagen	No a magnet always have two poles.So the the voicecoil will interact with both.

16th January 2009, 01:25 AM	#4
Clipped diyAudio Member Join Date: Mar 2005 Location: home	you only need 1 pole for the voice coil to move.

16th January 2009, 01:34 AM	#5
HK26147 diyAudio Member Join Date: Jan 2008	you answered your own question. Audio is AC and does the change of attraction/repulsion in the voice coil.

16th January 2009, 10:04 AM	#6
Clipped diyAudio Member Join Date: Mar 2005 Location: home	just wanted to double check before i drop $200 on NEO bars to make a sub.

16th January 2009, 11:15 PM	#8
HK26147 diyAudio Member Join Date: Jan 2008	There are a variety of transducers that use only 1 pole of a bar magnet such as the ribbon tweeter on this page: http://www.lautsprechershop.de/hifi/aka_hoch_en.htm http://www.visaton.com/bilder/sonsti...utsprecher.gif Audio Magazine had a construction article ( 70's ) orienting neo bars magnets in V's on both sides of the membrane. Perhaps an unconventional design is in mind?