Speaker Magnet Re-charge service in India

Hari Iyer

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Do you have any company in India who does old vintage speakers magnet re-charge. I have done some work in this area and the speakers benefit a lot with the magnet re-charge. Agreed speakers dont loose their magnetic property but they for sure loose their strength over age. Having a speaker magnet recharge service will allow the old vintage speaker to gain their lost strength. Even some speakers purchased in the 90's can benefit with their magnet recharge if they are not being used currently due to loss of juice in them.

Its similar to a completely discharged car battery being charged at a battery vendor.
 
I have done some work in this area and the speakers benefit a lot with the magnet re-charge. Agreed speakers dont loose their magnetic property but they for sure loose their strength over age. Having a speaker magnet recharge service will allow the old vintage speaker to gain their lost strength. Even some speakers purchased in the 90's can benefit with their magnet recharge if they are not being used currently due to loss of juice in them.

Its similar to a completely discharged car battery being charged at a battery vendor.

Hi Hari,
If original speaker is charged 1 Tesla/10,000 Gauss.
1.Then to what extent we can re-charge it to?
2.re-charging to 2-Tesla/20,000 Gauss possible?
3.how many decibels will be increased by this ? I for sure believe powerful motors are sensitive.
4. What are the limitations or restrictions for re-charging speaker magnets?
5. I meant is ther a re-charge limitation for specific magnet types Eg : Alnico, Neodymium, Ferrite, Ceramic etc. I know both Alnico & Neodymium can go upto 2.4 Tesla and Ferrite & Ceramic can go upto 2.0 Tesla.
6. Can we re-charge the speaker which still have original cones or need to be re-charged before reconing?

Thanks in Advance !

Regards
IRONICAL
 
Last edited:
Hi Hari,
If original speaker is charged 1 Tesla/10,000 Gauss.
1.Then to what extent we can re-charge it to?
2.re-charging to 2-Tesla/20,000 Gauss possible?
3.how many decibels will be increased by this ? I for sure believe powerful motors are sensitive.
4. What are the limitations or restrictions for re-charging speaker magnets?
5. I meant is ther a re-charge limitation for specific magnet types Eg : Alnico, Neodymium, Ferrite, Ceramic etc. I know both Alnico & Neodymium can go upto 2.4 Tesla and Ferrite & Ceramic can go upto 2.0 Tesla.
6. Can we re-charge the speaker which still have original cones or need to be re-charged before reconing?

Thanks in Advance !

Regards
IRONICAL
I am not much aware of the technicalities involved. I just tried magnetising some vintage speakers lying with me. You can try feeding around 5 Hz to 10 Hz to a driver and measure before and after. I think that will be safer than feeding DC.
 
I am not much aware of the technicalities involved. I just tried magnetising some vintage speakers lying with me. You can try feeding around 5 Hz to 10 Hz to a driver and measure before and after. I think that will be safer than feeding DC.
1.It seems first you must have tried feeding DC.
2.By feeding 5 hz to 10 hz what we going to derive?
3. I wanted to re-charge vintage ceramic motor speakers without cones to maximum possible charge like may be 2-2.4 Tesla if it can be done !
 
1.It seems first you must have tried feeding DC.
2.By feeding 5 hz to 10 hz what we going to derive?
3. I wanted to re-charge vintage ceramic motor speakers without cones to maximum possible charge like may be 2-2.4 Tesla if it can be done !
Feeding DC needs to be monitored for current else the coil can burn. You can water-cooling the magnet by dipping the magnet in a water bowl when doing so. The power supply used for doing this needs to be regulated PS. also do not feed more than 5v DC.
Do not exceed DC power more than 5 watt to your driver.
 
I won't be doing this by myself !
I would be giving my drivers to a friend who does this job.
I never discussed anything regarding these things in detail but I wanted to know little bit about the process before handing my drivers.
Kindly answer whether we can re-charge beyond (2.4 Tesla) to what the original charge (1 Tesla) was ?
 
I won't be doing this by myself !
I would be giving my drivers to a friend who does this job.
I never discussed anything regarding these things in detail but I wanted to know little bit about the process before handing my drivers.
Kindly answer whether we can re-charge beyond (2.4 Tesla) to what the original charge (1 Tesla) was ?
Don't know, it will require higher voltage/ current to do that. The driver should be able to withstand high current through the voice coil. The voice coil can short if it can't handle high temperature. You can try if you have nothing to loose.
 
When I added additional magnets on my OB driver, it ruined the mids and highs making it very shrill. Needless to say, I removed them immediately.
 
Folk's over here are discussing topics which are way beyond to their limits. This is all assumptions which are nowhere near to the reality. You cannot assume things out of the theory. Cannot change the law of physics with your own assumptions.
If you have a point ... Prove it with some theoretical
aspect supportive with some illustrated diagrams please.....
 
Dear Sidewinder,
I'm sure you can Prove it with some theoretical aspects supporting with some illustrated diagrams as you felt the discussed topics here are way beyond to their (whose?) limits & with full of assumptions which are no where near to the reality.
I believe whatever you said are True !

Regards
IRONICAL
 
Dear Sidewinder,
I'm sure you can Prove it with some theoretical aspects supporting with some illustrated diagrams as you felt the discussed topics here are way beyond to their (whose?) limits & with full of assumptions which are no where near to the reality.
I believe whatever you said are True !
Regards
IRONICAL

To understand a Loudspeaker magnetic circuit (motor structure) you will first got to know how this circuit is working.
(A) There are 2 types of magnetic field paying into action in a loudspeaker magnet....
1. DC or (static field).
2 AC field (generated)... when the coil is moving.

(B) The entire magnet assembly's main focusing point is the gap geometry. The advance engineering in a Loudspeaker is to get a linear or radial semmetrical feild between the T-yoke and Top plate.
And to focus the fringe feild up and below the gap more and more into the radial gap.
Several patented design had been implemented to achieve the highest and efficient gap strength with a semmetrical flux lines.
To know more and more about this one has to explore the unlimited datasheet and white papers on Loudspeaker magnet modeling and design.
The T-yoke or the return structure of a magnet assembly with the ring magnet in between and the top washer on the top is a cyclic path of magnetic field which flows from Noth to South or South to North .... between the gap width at the edge of the top washer and pole piece upper circumstance of the T-yoke.
The thickness of the top plate is the so called... "Gap-Height". This thickness is the main area of the entire magnetic assembly which has the strongest magnet energy.
Adding an extra magnet to the rear of the T-yoke will not do any better to the cyclic flow of the existing magnet circuit bringing any change to the actual gap geometry.
Apart from this many design had been implemented by adding an extra magnet on top of the pole piece for achieving linearity and suppressing flux modulations.
Generally rear attached magnets charged with an opposite polarity are used sometimes to sheild the entire magnet structure to prevent any leaking flux which can effect nearby electronics such as cathode ray tubes ... etc
The motor structure faces some real challenges in regards to eddy currents, inductance stabilization, flux stabilization, Fringe or leakage feild (around the gap), generation of 2 & 3rd harmonics, and many other issus related to temperature, offset DC, over excursion and bottoming.
Designer and engineers all around the globe are developing and bringing out new ideas and technology to overcome these serious issues and problems.
If only adding an extra magnet at the rear would increase the efficiency of the Loudspeaker then the designer would have simply used an oversized magnet intially. It is not that simple. Selection of a magnet size is a part of a particular loudspeaker design intended for a specific use with a specific parameters.
This discussion is endless ... it will further get complicated and can get offtrack.
I guess there a several books and information out there online to know more and more on this.
Thank you
Vivek
 
Got a US Patent later for the application process.

That's wonderful. And congratulations.

May I ask what do you do professionally? Looks like you are into some type of research. In case this is a sensitive info or involves national security, please don't bother to answer that.

Sorry for being off-topic.
 
Thanks. Stating from first year in college in 1989 till 2005, I was into intensive material science research for futuristic devices including superconductors. A visit by a jeweler from Jaipur got me interested in gemstone color enhancement field. Me and my father ended up inventing a process or rather applying device fabrication process to enhance natural topaz in different colors as opposed to just one color done in Russian nuclear reactors at that time and even today. Got a couple of US Patents. We own our lab now.

Audio been a passion since I was 8 and full range drivers and tubes is what I love today.

Magnet assemblies were key to developing above process and is very similar to what DIYers use for their long planar tweeters. And I built my machine at a very small fraction of US branded prices.

Awesome. Truly remarkable. I'd like to thank you for sharing your experience. It's always bettter to have someone like you around. And congratulations again!
 
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