Full range planar speaker using neo magnets

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a.wayne

a.wayne

Member
Joined 2008
tinitus said:
hey wayne
just a small note
remember to have front and back magnet with N to N towards each other, and S to S
if you choose front/back N to S, then you will get sidewards movement instead

one advantage is that front and back magnets wont attrackt each other, thus wont clash together

though I doubt its simple
magnets do strange things
and the field may not behave as intended

before buying all those expencive magnets, I suggest to build a small model, to see how it behaves
and its very tricky to assemble
you can only handle one magnet at a time
do not try to make larger sections
those magnets are impossible to control in multiples
Click to expand...

Trickey , huh ?

I was planing on having common polarity facing each other for a start using plates as oppose to perforated sheet as per James.

The Perf sheet would make for a easier go as a prototype. Standard ferrite magnets (domino style) are in expensive here 36.00 per 100 ....
 
T

tinitus

Ex-Moderator R.I.P.
Joined 2005
a.wayne said:
Trickey , huh ?
Click to expand...

yeah, very

many years ago I made a big woofer planar using steel bars
about 5mm thick, and 25mm wide
I thought it would be strong enough to hold sidewards draft
Hell, those "weak" ceramics bent those steel bars sidewards like nothing
remedy was easy enough, just small pieces of wood here ad there did the trick

but it still tells how much power to handle
and those were ceramics
now its much stronger neos
I have been looking at neos for rubanoide, N42-N50 quality
I was shocked when I found that summed power lift fore each channel would be close to lifting a small car

just a note of caution :D
:)

btw, honestly, I wouldnt dream of using a big planar for anything but the lowest bass
I have no idea how Jamesbos/Henry manage to do the impossible
 
J

JAMESBOS

Member
Joined 2007
:D:cool:having sorted out my first p/p frp I will be building a pair of p/p frp speakers using neo magnets size 50 x 12.7 x 3 mm. Then I will rebuild the 40 kilo black speakers covered in tube material, which have ferrites doubled up. So I can use the doubled up magnets for a p/p design. Should be louder for the same number of magnets and just one more piece of wood heavier. Just needs a slight re-design. Wish me luck!!
 
J

JAMESBOS

Member
Joined 2007
The wood has arrived using MDF for different thickness of magnets i.e. 6 mm wood for the 3mm neos,9 mm wood for the 6 mm neos and 15 mm wood for the 10 mm ferrites. Although 13 mm would be best for the 10 mm ferrites, but they don't sell this thickness. Have dismantled my21" x 24" speakers for the 3 mm neos, just need to cut the wood to size 600 mm x 400 mm and build the push pull full range planars 20 to 20k frequency. Then the same size using 6 mm neos. Then the doubled up ferrite ones covered in black tube material weighing about 40 kilos, will be rebuilt into my push pull design. This should keep me occupied for some time, should be very exciting and quite hard work for a 72 year old.:eek:
 
mavric

mavric

Member
Joined 2009
Jamesbos,
I have noticed that you have been working on this for three years now. I have read most of the post as it is over five pages long. Can you kindly post a pic of project? Your age has wisdom and I am interested in the view of what your creation looks like, aside from the cost,WOW, thats alot of money.
Kind regards, Mav.
is there any way you can provide any picture, please?
 
mavric

mavric

Member
Joined 2009
Very much respect!

Just wanted to get a taste if "your" project. We can all discuss words and theories, but a picture is worth a thousand words. 72? I have my father whom is around your age, helped me build my Esl hybrid, I could not have done it with out him.
Kind Regards, Mavric:)
 
J

JAMESBOS

Member
Joined 2007
If you go to post 44 you will see the pictures of my push pull frp made out of an old ikea cupboard my grandson gave me. I have only been working on the push pull design for a couple of weeks. I am taking pictures as I go along and will be putting these on the same site. I hope it doesn't rain today, got to cut the wood outside.:)
 
J

JAMESBOS

Member
Joined 2007
Have finished my pair of push pull frp's. They sound great also are only 60 x 40 cms. I will be dismantling all my planars I have built over the last twenty years! At the moment I am rebuilding my doubled up planars that weigh over 40 kilos, which caused my fall. I am placing the magnets on the steel sheet at this moment in time can't wait to listen to them when they are finished. They will be more sensitive and lighter in weight, with more control over diaphragm with it being a push pull design. I have tweaked the diaphragm suspension system to tighten it up. All the best bits have come together in this design. Lucky me.:D
 
J

JAMESBOS

Member
Joined 2007
rebuild

Have rebuilt one of my first full range planar designs, which I built 20 years ago. The alu tape was still firmly stuck to the plastic. Very good glue!!
I am very pleased with the outcome Using 4.5 mm tape makes a big difference to the sensitivity. Also my new method of tightening and fixing the membrane is a very big improvement on my original method. It also weighs less and even I can easily pick it up, when compared to my original which used a lot of angle iron.
This new design is more sensitive than my 60 x 40 cm design using neos. I will be rebuilding the other one of the pair when the weather improves
The mdf sheet 2440 cm x 1220 cm is been in my kitchen and hall for 3 weeks now.!!! It was damaged when I received it but the seller has not replaced it!!??Wickes!! But i'm not bothered any more. Just want to rebuild all my old 4' ferrite full range planars and all my old neo ones as well. These will be a big improvement on the original designs, and they will look a lot better. Can't wait. HENRY:)
 
jmillerdoc

jmillerdoc

Member
Joined 2009
I picked up about 50 1"x1/2"x1/8" neo magnets not too long ago. I wanted to try to make something with these just to toy with. The magnets field is across the thin section as if it were a domino the face with dots would be north and the other side south. I am wondering about orientation of the field in relation to the foil/film driver. Can someone explain to me how the orientation must be in relation to the fields. I wanted to build a ribbon using 10 of these stacked end to end giving me a 10" high field. I was thinking that if I spaced another stack about an inch apart where one side pointed the north field towards the other sides south, thus giving a flux across an inch wide by ten inch tall area. Then I would suspend the ribbon between the stacks, all current going the same direction down the ribbon. Maybe 15 or so traces of foil down the ribbon.

Is this the correct orientation of the field across the ribbon to effect the proper movement of the ribbon whe a current is applied?

Thanks,
Jeff
 
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