Push-Pull Planars with small neo magnets?

[rsuski]

Has anyone had any experience using smaller (1/4" x 1/4" x 1/4" N45) magnets in arrays on both sides of a diaphragm? After modeling them it looks like they have a usable (.5+) field for up to a 1/2" gap and would in addition be adequate for modest ribbon tweeters.
There cost is so attractive ----- but since no designs I have seen so far use neo magnets that small I wanted to inquire with experienced builders before I got myself in too deep.
I am planning on etching a voice coil print into 4um aluminized mylar for the diaphragm. Tweeter would be a 1/4" ribbon, reminiscent of maggies.
Any thoughts on this would be appreciated.
Regards,

 

[george a]

rsuski

At the risk of appearing biased-(which i am) have you considered a simpler ribbon construction method for something that small- i thought some of the maggies used ribbon tweeters of this type also...

see http://www.diyaudio.com/forums/attachment.php?s=&postid=1420222&stamp=1202217304

The magnets in this are 10x10x10mm and 11mm apart...mounted onto steel frame same thickness as the magnets.

they do however require transformers
no reason this couldn't be done with smaller magnets.

cheers
George

 

[rsuski]

Mini Ribbon for push-pull planar

Thank you George for your timely response. I had seen that post and it gave me hope that my planned half/size magnets could be used for the 24" ribbon as well. I am unsure still - even with the flux modeling, if the coupling of all the little magnets may at some point become a field or construction difficulty issue. I plan to match the vertical ribbon with a dual sided planar midrange panel using the same magnets if practical.
I sincerely appreciate your feedback
Regards

 

[george a]

Hi Rsuski

have a look at this

http://www.goodsoundclub.com/GetPost.aspx?PostID=3766


magnets on mine were a pig to align whilst setting place with super glue

Cheers

George