I have two pyramid 1295's which are basicaly ugly cheap car subwoofers which were good for a first learning experience on designing out a ported box and building it, but are realy crappy for any sort of listening. I was considering the idea of taking them apart as gently as I could, and then using the two magnets and pole pieces and welding / gluing them together, and then using one voice coil mounted in the middle of this double length magnetic field in order to have a muich longer linear excursion range. I figure the paper pulp cone, foam surround, plastic dust cap, etc are all pretty much trashable. Then using this new asembly and prob the 2nd voilce coil as a spacer mount a new smaller cone with a bycicle inner tube as a big surround , and maybe do a double surround like mentioned in the pasive radiator thread in order to get arond the issue of a spyder to handle that excursion. Does this sound at all possible to anyone or a complete waste of time to even attempt? I dont care if it is "musical" or very accurate, Im mainly interested in this as a project since it is nearly free and the coolness factor f I can create something with incredible excursion capabilities.
As nobody else seems to want to answer, i'll start.
It sounds to me like a waste of time to attempt. I cant see it working full stop.
Having said that, I have taken on some stupid/impossible projects myself in the past so If you feel that you want to try anyway then go for it. You have nothnig to lose except some crap drivers and time. And you are bound to learn a little (or a lot) which will be of future benefit.
If you do try, let us know how it goes.
It sounds to me like a waste of time to attempt. I cant see it working full stop.
Having said that, I have taken on some stupid/impossible projects myself in the past so If you feel that you want to try anyway then go for it. You have nothnig to lose except some crap drivers and time. And you are bound to learn a little (or a lot) which will be of future benefit.
If you do try, let us know how it goes.
Designing and building a speaker is no simple task. Their is a critical balance between mechanical and electrical caracteristic affecte by an infinite number of factor. By modifing a driver you will probably not get satisfactory result and any imperfection will greatly reflect in the final sound.
Hi,
Unless your existing arrangement is already excursion-limited due to weak magnets i.e. nowhere near 'hits the end stops', I don't think you have much to gain here. There is only so much extension any driver will accomodate for due to the cone, surround and depth of gap etc., and trying to exceed this is likely to give rather poor results, I would guess.
However, as has already been said, if you are only doing it out of curiosity, there is little to lose, but you may have a job lining up the annular rings within which the voice coil resides and moves, depending on how close tolerances they are.
Any misalignment here will produce some odd results, and a lot of unwanted scraping noises!
Finally, I wouldn't try your welding suggestion, as (most) magnets don't like heat very much, and you can destroy (or at least substantially reduce) the magnetism with a lot of heat.
Regards,
Unless your existing arrangement is already excursion-limited due to weak magnets i.e. nowhere near 'hits the end stops', I don't think you have much to gain here. There is only so much extension any driver will accomodate for due to the cone, surround and depth of gap etc., and trying to exceed this is likely to give rather poor results, I would guess.
However, as has already been said, if you are only doing it out of curiosity, there is little to lose, but you may have a job lining up the annular rings within which the voice coil resides and moves, depending on how close tolerances they are.
Any misalignment here will produce some odd results, and a lot of unwanted scraping noises!
Finally, I wouldn't try your welding suggestion, as (most) magnets don't like heat very much, and you can destroy (or at least substantially reduce) the magnetism with a lot of heat.
Regards,
28 inch woofers
How about leaving your drivers intact but adding a *much* larger cone? The existing roll surround would be like a secondary spider and you could use your rubber bicycle tube as your new surround as you suggested. Still some tricky mechanical issues but you are much more likely to have some measure of success (and fun) if you don't pull the magnet and coil assembly apart. Let us know how you go if you decide this way.
/Circlotron - plants seed of idea in someone else's head so they do the hard work of his experiment.
How about leaving your drivers intact but adding a *much* larger cone? The existing roll surround would be like a secondary spider and you could use your rubber bicycle tube as your new surround as you suggested. Still some tricky mechanical issues but you are much more likely to have some measure of success (and fun) if you don't pull the magnet and coil assembly apart. Let us know how you go if you decide this way.
/Circlotron - plants seed of idea in someone else's head so they do the hard work of his experiment.
28 inch woofers
How about leaving your drivers intact but adding a *much* larger cone? The existing roll surround would be like a secondary spider and you could use your rubber bicycle tube as your new surround as you suggested. Still some tricky mechanical issues but you are much more likely to have some measure of success (and fun) if you don't pull the magnet and coil assembly apart. Let us know how you go if you decide this way.
/Circlotron - plants seed of idea in someone else's head so they do the hard work of his experiment.
How about leaving your drivers intact but adding a *much* larger cone? The existing roll surround would be like a secondary spider and you could use your rubber bicycle tube as your new surround as you suggested. Still some tricky mechanical issues but you are much more likely to have some measure of success (and fun) if you don't pull the magnet and coil assembly apart. Let us know how you go if you decide this way.
/Circlotron - plants seed of idea in someone else's head so they do the hard work of his experiment.
Reply to Jared
Taking apart a absolute crap speaker completely,will distroy it.
And there's no point re-coning some crap make of speaker.
A lot of car audio subwoofers are poor quality,except a few which i like[but are expensive] [JL Audio,Rockford Fosgate,Atomic,Focal,Fusion,and the more expensive Pioneer]
A could just carefully cut away the foam or rubber surround on the awful woofers.But the way to get the most excersion is longer voice coil,deep double dampener,and very thick ,very flexible rubber.But i guess the voice coil former on your really cheap and nasty speaker drivers,won't take much physical or themal abuse,if you modify it.
I've only modifyed one odd speaker,but not the surround,but the dustcap[because it was badly torn].
I advice you to sell the pair of these subwoofers,depending on whether they don't buzz[ don't distort on bass notes],and get 1 better subwoofer.
The advice for bigger excersion is measured in Xmax and X Mech,if you don't have a clue what i'm talking about;then look for maximum linear excersion when buying some new or 2nd hand drivers.If maximum linear excersion is not printed on the speaker packaging,then at least a speaker with a deep basket[deep frame] and thick large surround [or cone edge].A speaker having more excersion peak to peak than the other doesn't make it a better sounding speaker,but the more excersion the speaker can handle the more mechanical abuse it can take.
A speaker that can take a lot of thermal abuse has a big voice coil 4 inch diameter,kapton coil former,vented pole piece,high temperature copper voice coil which is made of thicker copper wire.
A combination of both these makes a good strong subwoofer,but it still can sound unnatural and have a more limited frequency
range.
Taking apart a absolute crap speaker completely,will distroy it.
And there's no point re-coning some crap make of speaker.
A lot of car audio subwoofers are poor quality,except a few which i like[but are expensive] [JL Audio,Rockford Fosgate,Atomic,Focal,Fusion,and the more expensive Pioneer]
A could just carefully cut away the foam or rubber surround on the awful woofers.But the way to get the most excersion is longer voice coil,deep double dampener,and very thick ,very flexible rubber.But i guess the voice coil former on your really cheap and nasty speaker drivers,won't take much physical or themal abuse,if you modify it.
I've only modifyed one odd speaker,but not the surround,but the dustcap[because it was badly torn].
I advice you to sell the pair of these subwoofers,depending on whether they don't buzz[ don't distort on bass notes],and get 1 better subwoofer.
The advice for bigger excersion is measured in Xmax and X Mech,if you don't have a clue what i'm talking about;then look for maximum linear excersion when buying some new or 2nd hand drivers.If maximum linear excersion is not printed on the speaker packaging,then at least a speaker with a deep basket[deep frame] and thick large surround [or cone edge].A speaker having more excersion peak to peak than the other doesn't make it a better sounding speaker,but the more excersion the speaker can handle the more mechanical abuse it can take.
A speaker that can take a lot of thermal abuse has a big voice coil 4 inch diameter,kapton coil former,vented pole piece,high temperature copper voice coil which is made of thicker copper wire.
A combination of both these makes a good strong subwoofer,but it still can sound unnatural and have a more limited frequency
range.
I am going to have to give my predictions for this experiment as being a failure, although that doesn't mean it shouldn't be done for fun. I Do not think you will be able to properly position the voice coil in any way that would allow it to make use of the magnetic feilds from both magnetic structures. If I understand what you are sating correctly, it seems as though there will be a gap between the two magnets on the driver and no matter where you position the voice coil in relation to the magnets, you will wither have no better a situation than you started with or a worse one. Someone please tell me if I am wrong.
If the voice coil's idle position is between the two magnets, the eldctrical pulse that charges the voice coil will not be able to decide between going to the magnetic field above it or beneath it. If the voice coil is placed above or within the magnetic feild of the top magnet, you have no better a situation than you started with, and if the voice coil travels down far enough, it will only get slowed down by the magnetic feild of the lower magnet, trying to attract it down, away from it's return stroke back to the idol position.
And by the way, I have to put in a good word for at least ONE kind of Pyramid subwoofer. I have heard Pyramid's Super Blue 12's and 15's in multiple applications and they can hold their own with about any subwoofer out there, at least they could 5 to 10 years ago. If they are still as good as they used to be, they should be considered the best bang for the buck in audio.
If the voice coil's idle position is between the two magnets, the eldctrical pulse that charges the voice coil will not be able to decide between going to the magnetic field above it or beneath it. If the voice coil is placed above or within the magnetic feild of the top magnet, you have no better a situation than you started with, and if the voice coil travels down far enough, it will only get slowed down by the magnetic feild of the lower magnet, trying to attract it down, away from it's return stroke back to the idol position.
And by the way, I have to put in a good word for at least ONE kind of Pyramid subwoofer. I have heard Pyramid's Super Blue 12's and 15's in multiple applications and they can hold their own with about any subwoofer out there, at least they could 5 to 10 years ago. If they are still as good as they used to be, they should be considered the best bang for the buck in audio.
i'm going with circlotron also. i once had the misfortune of having a friend give me some very good speakers, but the magnet had come off the basket on one of the drivers. one week (many offensive words, and what i assume to be a mild stroke) later, and they were fixed. i promptly sold them off, and never want to see them again. this was painful putting it where it was SUPPOSED TO GO. i can't possibly imagine the torture you will put yourself through if you go ahead with your plans.
best of luck either way.
(you will need all the luck you can get
)
best of luck either way.
(you will need all the luck you can get
)The Paulinator - these are 1295's the biggest 12 they had back in the day.. 70 oz magnet, 350 watt RMS.. I had some 1270s at one time too and they were similar sounding, very capable SPL wise, bu not nice sounding at all.
What I envisioned was taking te two magnet assemblies, and then taking them entuirely apart. Chop a pole piece off of one assembly and weld it to the other and then use angle grinder to smooth it out in order to have a double length internal guide for the voice coil. then re glue the magnets back into place on this new assembly, so all i have done at this point is to double the length of the magnetic field (corect magnet orientation of course)
for that point I was not too sure on as the voice coil is wound on that orange colored plastic that wont join end to end very easily. I do liek th eidea of makng a 20+ inch woofer tho.. not a bad idea at all.. and with the size of this magnet assembly it would not look too disproportionate i guess! http://12.41.28.254/pyramid/PW1295US.JPG
is a pic of the driver. Interestingly enough, 6 years ago pyramid supplied specs on their drivers.. they dont suply any at all anymore !! Talk about shady....
anyways, I am going to do the bigger cone with jsut a double magnet idea, and if possible at all offset the coil farther into the gap wiht th e2nd coil as a spacer. I guess I will get pics of the attempt. the hardest part is going to be getting the ceramic magnets unglues wthout shattering.
What I envisioned was taking te two magnet assemblies, and then taking them entuirely apart. Chop a pole piece off of one assembly and weld it to the other and then use angle grinder to smooth it out in order to have a double length internal guide for the voice coil. then re glue the magnets back into place on this new assembly, so all i have done at this point is to double the length of the magnetic field (corect magnet orientation of course)
for that point I was not too sure on as the voice coil is wound on that orange colored plastic that wont join end to end very easily. I do liek th eidea of makng a 20+ inch woofer tho.. not a bad idea at all.. and with the size of this magnet assembly it would not look too disproportionate i guess! http://12.41.28.254/pyramid/PW1295US.JPG
is a pic of the driver. Interestingly enough, 6 years ago pyramid supplied specs on their drivers.. they dont suply any at all anymore !! Talk about shady....
anyways, I am going to do the bigger cone with jsut a double magnet idea, and if possible at all offset the coil farther into the gap wiht th e2nd coil as a spacer. I guess I will get pics of the attempt. the hardest part is going to be getting the ceramic magnets unglues wthout shattering.
Bad idea!
I would advise againt any grinding on or around the pole piece of your magnet, I just learned that the hard way.
I had a pair of old no name 12" and the spider and surround was crused on one of them. So i took the exacto knife to it, Cut the spider out and the surround, then while removing the glue residue from the basket i got the bright idea to just use a dremel and grind it away, Bad idea, what i was left with was a buch of grinding dust that is magnetized and stuck in the voice coil gap, Even though i thouhroly taped it off. I was planing on finding a replacement spider and surround but it is not worth it now, too much work to try and remove the dust, if i even can.
I thought it would be a cool experiment, my first speaker repair but it turned out ugly. so now i'm gonna just use the basket and turn it into a passive radiator, and use it with the other 12"
I would advise againt any grinding on or around the pole piece of your magnet, I just learned that the hard way.
I had a pair of old no name 12" and the spider and surround was crused on one of them. So i took the exacto knife to it, Cut the spider out and the surround, then while removing the glue residue from the basket i got the bright idea to just use a dremel and grind it away, Bad idea, what i was left with was a buch of grinding dust that is magnetized and stuck in the voice coil gap, Even though i thouhroly taped it off. I was planing on finding a replacement spider and surround but it is not worth it now, too much work to try and remove the dust, if i even can.
I thought it would be a cool experiment, my first speaker repair but it turned out ugly. so now i'm gonna just use the basket and turn it into a passive radiator, and use it with the other 12"
At least try this idea out on a pair of low grade speakers first, then if it is a sucess - fine, but please don't hack into those big beasties before you try it the no - risk - no - tears way first. 
your nuts. plain and simple. and i wouldn't even consider welding. the minute you put even the smallest tack weld on, the alignment is shot. i too have had a lot of trouble with metal shaving in the pole piece (and unless you have a tig, there will be PLENTY of spatter). and from experience, if you get the magnets too hot, they will shatter. you are certifiably insane.
seriously, try is with some small cheap speakers first if you must.
there coming to take you away,
haha,
there coming to take you away,
hehe,
hoho, haha, to the the funny farm.
seriously, try is with some small cheap speakers first if you must.
there coming to take you away,
haha,
there coming to take you away,
hehe,
hoho, haha, to the the funny farm.
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