Changing, upgrading magnets on bass drivers

noobydoo

noobydoo

Active Member
Hi everyone. I have a pair of older technics sbl's. They have a 12 " woofers that are in great shape but while I had them apart while I was refinishing the cabs I noticed the magnets on the drivers were smaller than those on the 5" drivers on my paradigm center speaker. I have a pair of older 8" drivers I'm not using atm with a much larger heavier magnet on them. Would I be able to swap them with the mags on the technics. Same size voice coil. Just wondering, I realize I could mess up both sets of drivers, but they cost me almost nothing and I'm willing to experiment. Thx
 
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This does not sound like a good idea. Perhaps someone smarter than me can explain why, but drivers are designed - engineered - as a package. This is kind of like taking the cylinders out of one engine and putting them into another just because they're close to the same size. But the mag. field won't be the same...
 
I see what you're getting at, but to further the car analogy I was thinking it would be more along the lines of boring out the cylinders or maybe increasing the size of the intake valves. As for no one ever doing this, I know of drivers that are identical except for the magnets, Driver makers will upgrade magnets on older models. I'm not married to the idea, just thought it might be interesting to experiment with.
 
The critical questions seem to be: 1) will the larger magnet exceed the capabilities of the cone, voice coil etc.? and 2) What will it do to the woofer's parameters, such as frequency response, sensitivity, Q, resonant frequency, xmax, etc. The latter will determine how the speaker sounds, the former will determine whether it can handle it without exploding.
 
noobydoo said:
Hi everyone. I have a pair of older technics sbl's. They have a 12 " woofers that are in great shape but while I had them apart while I was refinishing the cabs I noticed the magnets on the drivers were smaller than those on the 5" drivers on my paradigm center speaker. I have a pair of older 8" drivers I'm not using atm with a much larger heavier magnet on them. Would I be able to swap them with the mags on the technics. Same size voice coil. Just wondering, I realize I could mess up both sets of drivers, but they cost me almost nothing and I'm willing to experiment. Thx
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Can't hurt xperment, just don't have great expectations. I've count that most magnet assists will be weaker if separated from original setup. Have fun,price is right..
 
Don't know much in speaker, you can always take the big magnet out of the 8" and stick it to the back of the speaker, that should add more flux without doing any invasive things.

I think it's a lot more complicate than just the voice coil is the same size. How deep the thing in the middle go into the voice coil make a whole lot of difference. Good luck in changing magnet, they stick and slam onto any magnetic material, this is precision work centering the magnet. I give you 95% chance messing up both speakers. It is my understanding that when they make speakers, they assemble them un-magnetize, then after assembly, they magnetize the magnet.

Try sticking the extra magnet at the back and see what happens.
 
You can simply glue it onto the existing magnet. This is easier than replacing it altogether, and gets you the strength of both magnets. Remember that you must connect them the hard way, i e the way that it doesn't want to stick together. Otherwise you reduce the magnetic strength.

Adding a magnet like this will increase the driver's sensitivity, so it'll play louder with less power. This is commonly done on full range speakers, and it may not sound so good in a multi way speaker, since the woofer will become louder than the rest of the drivers.
 
I second to leave it alone. The important question is whether it sounds good and you are happy with it. Don't like the see the small magnet, don't look at it!!! You will cause imbalance of the sound if you mug with the magnet.
 
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