Hey all,
I have a few 24" long x 7/16" x 7/16" magnets. They are kitchen knife holders (search Winco WMB24 on fleabay)
Anyway, am I better off stacking them or placing side by side to increase magnet force...this is for ribbon tweeter... These are not Neodymium but cheapies I picked up thinking they could work. Thought to try this before going with the expensive magnets...
I have a few 24" long x 7/16" x 7/16" magnets. They are kitchen knife holders (search Winco WMB24 on fleabay)
Anyway, am I better off stacking them or placing side by side to increase magnet force...this is for ribbon tweeter... These are not Neodymium but cheapies I picked up thinking they could work. Thought to try this before going with the expensive magnets...
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If you are making a ribbon tweeter then you want the strongest field you can get. Neodymium magnets are just so much stronger than everything else that unless you are making a large-scale device where you can make up for inefficiency by sheer size then you will want to go for the expensive magnets.
You have to stack them in order to make them stronger.
They are just like batteries in series, everytime you double the stack you double the strength.
jer 🙂
They are just like batteries in series, everytime you double the stack you double the strength.
jer 🙂
As far as I know, all quality ribbon tweeters use neodymium or better magnets. The problem with ribbon tweeters is getting a large magnetic field in a small area (this is referred to as high magnetic flux density). There is a limit to the maximum field you can achieve by sticking magnets together without it becoming far too large to be usable, if your magnets are not very strong then you can't even come close to what would be achieved with neodymium.
Yeah, I knew I was taking a chance on these magnets...just don't know if I want to drop 4300 on magnets at the moment...anyone know an inexpensive vendor of Neodymium magnets? looking for a 5 - 6 foot tall tweeter....
One other factor is how are the magnets magnitized that is are the poles on opposite ends or opposit sides of the magnet, Usualy a round bar like that would have the poles on the ends probably not what you would want. And look on ebay you should be able to get enough bar neodyyminum magnets for your project for $100 or less. And with a 6 ft tweeter I would think you could get by with a little less flux unless you just have to have a sesnitivity of over 100 db/w .
Yup, I have a pair of Cal Sig Tweeters just sitting around...wanna try longer and DIY. I have the amps to do the 1 ohm DCR (Krell HSA, Pass, etc)
The Neo magnets on ebay worry me. Wa s looking at 2" x 3/4" 1/8"thk at 17 pounds pull should be good...6 for $10 puts me at $200, and then the crazy shipping...
The Neo magnets on ebay worry me. Wa s looking at 2" x 3/4" 1/8"thk at 17 pounds pull should be good...6 for $10 puts me at $200, and then the crazy shipping...
Go to somewhere like AliExpress.com - Online Shopping for Electronics, Fashion, Home & Garden, Toys & Sports, Automobiles from China. if you want low price and (usually) free shipping. It may be hard to find ones as strong as US made, but they should all be pretty close, it's a mature technology.
Don't think so. I don't think Neodymium was available when Magnepan designed them +30 years ago.
If you want to use Neodymium magnets, take a look at http://www.dahlbergaudiodesign.se/engelska/del1.htm
There are four rows of magnets on each driver, many of them... About $ 2,20/magnet here in Sweden.
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I didn't think so...the Apogee Cal Sig tweeters I have also do not appear to be Neodymium...so they can work and sound good and not be neodymium...best to use Neodymium anyway...I will check Aliexpress regardless....
I remember reading that the original Magnepan's magnets were something similar (if not the same) as the flexible Refrigerator type magnet's that are used on the door seals.
I once had a roll of some very strong type of Vinyl magnet that comes in a roll (not cheap) that was very strong, it is used to make Magnetic signs and such, we used to use it to make Fridge magnets of our logo for Woodshed studios back in the 90's.
I tried to use this for a Speaker design but the NS poles were very small spaced at less than an 1/8" per section, and it was very difficult to get the conductors to line up properly with the field.
For a while at the time you could get the door strip magnets that were very strong and Cheap!!
But I never pursued it because there was just to much going on with the studio and working as a chef.
Besides we had plenty of sound power, that was when my friend had got the Apogee's that I now have.
Having studied them very hard, I said to myself "This can't that simple".....Ahhhh,ha,ha,ha,ha!!!
It is...Just that it isn't in practice !!!! He,he,he 😉
But, Neodium's barely existed back in those days.
Usually only in Hard Drives!
As far as I know all of the Apogee's (and Magie's maybe later on) used ceramic magnets, and I figured out that the ones you could buy at Radio Shack where about the same strength only thinner.
Anyhow I have finally found the stack I have from those days and they are still good!
I had more, that where unmounted but some uncontrollable whirlwind took them away when I was not watching!! 😉
I had enough too build another one that is in the picture.
Unfortunately these are all super glued together,But maybe I can still cut them in half some how and make two good tweeters out of them. 😉
Yet, I am still pursuing ESL's. He,he,he
A few good amps have been ruined on those experiments, but it worked and they sounded great!!!
jer 🙂
I once had a roll of some very strong type of Vinyl magnet that comes in a roll (not cheap) that was very strong, it is used to make Magnetic signs and such, we used to use it to make Fridge magnets of our logo for Woodshed studios back in the 90's.
I tried to use this for a Speaker design but the NS poles were very small spaced at less than an 1/8" per section, and it was very difficult to get the conductors to line up properly with the field.
For a while at the time you could get the door strip magnets that were very strong and Cheap!!
But I never pursued it because there was just to much going on with the studio and working as a chef.
Besides we had plenty of sound power, that was when my friend had got the Apogee's that I now have.
Having studied them very hard, I said to myself "This can't that simple".....Ahhhh,ha,ha,ha,ha!!!
It is...Just that it isn't in practice !!!! He,he,he 😉
But, Neodium's barely existed back in those days.
Usually only in Hard Drives!
As far as I know all of the Apogee's (and Magie's maybe later on) used ceramic magnets, and I figured out that the ones you could buy at Radio Shack where about the same strength only thinner.
Anyhow I have finally found the stack I have from those days and they are still good!
I had more, that where unmounted but some uncontrollable whirlwind took them away when I was not watching!! 😉
I had enough too build another one that is in the picture.
Unfortunately these are all super glued together,But maybe I can still cut them in half some how and make two good tweeters out of them. 😉
Yet, I am still pursuing ESL's. He,he,he
A few good amps have been ruined on those experiments, but it worked and they sounded great!!!
jer 🙂
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jer - Wow - with those mounted magnets, you are there...I like my ESLs, but for high highs, nothing (for me) beats a Tympani IVa type long tweeter...
As far as aluminum ribbons, I have been using thin kitchen foil run through my wife's crank spaghetti maker (cuts perfect 3/8" wide strips), then a cheapy crimper / pleater from Michaels (same as the one on ebay that sells for $50 for a whole $6).
Ribbon Pleater for DIY Ribbon Loudspeaker Tweeter | eBay
For quick experiments on 48" long tweeters - it works great....I gotta get back to those Apogee Cal Sig Tweeters again...
As far as aluminum ribbons, I have been using thin kitchen foil run through my wife's crank spaghetti maker (cuts perfect 3/8" wide strips), then a cheapy crimper / pleater from Michaels (same as the one on ebay that sells for $50 for a whole $6).
Ribbon Pleater for DIY Ribbon Loudspeaker Tweeter | eBay
For quick experiments on 48" long tweeters - it works great....I gotta get back to those Apogee Cal Sig Tweeters again...
There are 9 stacks on the board but i can cut it to make two sets of 4 for a pair of 8" long drivers.
I almost have to agree with you, I love my ESL's but the Apogee ribbons are almost the best I have heard for the highs.
ESl's make for great Midrange drivers.
My next adventure will Plasma drivers for the highs.
I used Plain ole .5mil Aluminium foil too and many of my first ones weren't pleated.
It seem that not having them pleated only limited it lower range a bit.
At the time driving them was very hard so I started working on a high current feedback amplifier with some FET's and opamp's but I never built it.
I didn't know enough about transformer design back then to implement them although I did wind one out of a 25.2V 2 amp core commonly found at Radio shack, But again another unfinished project that never got tested.
I may even still have that thing around here somewhere, at least I did a few years ago!!! He,he,he,he
I got the same pleater from Micheal's as well and it works great!!
I have found that if you pleat a sheet of foil and then turn the foil 90 dgrees and do it a again it gives the very light sheet a lot of rigidity!!!
layering a few sheets is even better and might make some sort of low frequency driver as well.
That was about the extent of my ribbon adventures so far then I got in to ESL's.
Cheers!!!
jer 🙂
I almost have to agree with you, I love my ESL's but the Apogee ribbons are almost the best I have heard for the highs.
ESl's make for great Midrange drivers.
My next adventure will Plasma drivers for the highs.
I used Plain ole .5mil Aluminium foil too and many of my first ones weren't pleated.
It seem that not having them pleated only limited it lower range a bit.
At the time driving them was very hard so I started working on a high current feedback amplifier with some FET's and opamp's but I never built it.
I didn't know enough about transformer design back then to implement them although I did wind one out of a 25.2V 2 amp core commonly found at Radio shack, But again another unfinished project that never got tested.
I may even still have that thing around here somewhere, at least I did a few years ago!!! He,he,he,he
I got the same pleater from Micheal's as well and it works great!!
I have found that if you pleat a sheet of foil and then turn the foil 90 dgrees and do it a again it gives the very light sheet a lot of rigidity!!!
layering a few sheets is even better and might make some sort of low frequency driver as well.
That was about the extent of my ribbon adventures so far then I got in to ESL's.
Cheers!!!
jer 🙂
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John.....if you drop the res. that feeds the bias too the panels.....not only well the top end open up an get sweeter....this setup is the best topend i have ever got out of any ESL mod......
youll get about 3db more output...... runing 5meg on my ML...an Acoustats....other say 10meg is good....but i even went to 3meg....an it worket fine.....
you may have to drop the bias back to the stock....on the Acoustat ....i have found i use less bias...an get more output .........gofig.....hehe
In the 90s i ran my Apogees Duitta mt ribbons with my 2+2s.....an it worket great....but made me mad as hell at how bad the topend was on the Acoustats.... made me move away from the Acoustat.....
This befor i setup my outboard bias....Acoustat stock 500meg bias feeder is the topend killer......the ml....60meg......
less you live were it vary dry.....like above 60-80 humity....then the 500megs well work....i gess... but 500meg it still rolls the top down.....
youll get about 3db more output...... runing 5meg on my ML...an Acoustats....other say 10meg is good....but i even went to 3meg....an it worket fine.....
you may have to drop the bias back to the stock....on the Acoustat ....i have found i use less bias...an get more output .........gofig.....hehe
In the 90s i ran my Apogees Duitta mt ribbons with my 2+2s.....an it worket great....but made me mad as hell at how bad the topend was on the Acoustats.... made me move away from the Acoustat.....
This befor i setup my outboard bias....Acoustat stock 500meg bias feeder is the topend killer......the ml....60meg......
less you live were it vary dry.....like above 60-80 humity....then the 500megs well work....i gess... but 500meg it still rolls the top down.....
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