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Magnetless Subwoofers

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=79275
Printed Date: March 29, 2024 at 2:39 AM


Topic: Magnetless Subwoofers

Posted By: coppellstereo
Subject: Magnetless Subwoofers
Date Posted: June 18, 2006 at 12:00 PM

How does a magnetless speaker/subwoofer work?

Thanks!



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Replies:

Posted By: DYohn
Date Posted: June 18, 2006 at 12:02 PM
coppellstereo wrote:

How does a magnetless speaker/subwoofer work?

Thanks!


There is no such thing.  Loudspeakers require magnets to function.  Where did you see a "magnetless" woofer?



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Posted By: Steven Kephart
Date Posted: June 18, 2006 at 12:15 PM

I suppose if you make the pannel large enough, you could make a subwoofer out of an electrostatic speaker.  Here's a link describing how they work: https://electronics.howstuffworks.com/question713.htm

The only other one I can think of is the prototype  Ionic speaker Adire Audio showed at CES this year.  But as it's a prototype of a developing, unreleased technology, you won't get a description how it works.





Posted By: church_of_bass
Date Posted: June 18, 2006 at 4:36 PM
the phoenix gold cyclone is a coneless woofer.  It does have a magnet, but it is not a conventional speaker.  It converts low frequency to kinetic energy with a rotary motion, moving air inside the structure of the speaker, rather than a linear motion moving air in front of and behind the speaker.  Never seen one in action, but it is a real cool idea.  As for magnetless, i don't know that they exist.

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Posted By: haemphyst
Date Posted: June 18, 2006 at 6:09 PM
DYohn] wrote:

coppellstereo wrote:

How does a magnetless speaker/subwoofer work?

Thanks!


There is no such thing.  Loudspeakers require magnets to function.  Where did you see a "magnetless" woofer?



No, Dave, they require magnetic FIELD to work. IF you were to wire a stator field OUT of phase to a voice coil field, it COULD work, but I doubt the efficiency would be worthy of the effort... Also, the waste of 50 percent of your amplifier power in the stator field would make many people think twice about it...

You are most likely correct, for now. They do not exist - commercially. But if *I* was able to devise one on paper (no proof-of-concept ever built) surely somebody out there with MUCH more money and brains than I have has certainly built such an animal...

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Posted By: DYohn
Date Posted: June 18, 2006 at 6:22 PM

Not to pick nits Dave, but an electromagnet is indeed still a magnet, it just may not be a permanent one.  And Steven, I believe the plasma field speaker systems I have read about use magnetic deflection coils to focus the energy (not sure if the Adire experimental system do or not, though.)  posted_image

Coppellstereo, are you talking about some of the newer shallow-mount woofers that appear to be nearly flat?  These use an inverted motor system and the magnet assembly is located inside the "cone" area - so to speak.



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Posted By: coppellstereo
Date Posted: June 18, 2006 at 8:30 PM
Actually yes - I was looking at a shallow mount subwoofer - the guy I was talking to called it 'magnetless', but upon further investigation I found the truth!  Thanks again

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Posted By: Steven Kephart
Date Posted: June 18, 2006 at 8:44 PM
DYohn] wrote:

P>And Steven, I believe the plasma field speaker systems I have read about use magnetic deflection coils to focus the energy (not sure if the Adire experimental system do or not, though.)  posted_image


No magnets at all.  It consists of one screen having a negative charge and the other having an AC signal voltage applied to it.





Posted By: Steven Kephart
Date Posted: June 18, 2006 at 10:07 PM

church_of_bass wrote:

the phoenix gold cyclone is a coneless woofer.  It does have a magnet, but it is not a conventional speaker.  It converts low frequency to kinetic energy with a rotary motion, moving air inside the structure of the speaker, rather than a linear motion moving air in front of and behind the speaker.  Never seen one in action, but it is a real cool idea.  As for magnetless, i don't know that they exist.

Phoenix Gold actually liscensed that technology from Servodrive.  It was a unique take however as the Servodrive units were belt driven models.  It does use magnets in the motor though.





Posted By: DYohn
Date Posted: June 18, 2006 at 10:27 PM

Steven Kephart wrote:

No magnets at all.  It consists of one screen having a negative charge and the other having an AC signal voltage applied to it.

Ah, so it's based on an ion pump to move the air.  Interesting.  I'll have to go see it one of these days!



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Posted By: Steven Kephart
Date Posted: June 18, 2006 at 10:57 PM
Yup, no moving parts at all.  A nearly massless speaker.





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