DIY ribbon info requested (constructing a ribbon unit)

[SpinMonster]

I wish to build a 26-36" ribbon like the one here:

"The tall neodymium ribbon". Part 1

I havent built anything like this before so I wish to go ahead with a 1000 dollar project. I am very good at fabricating but I need some tech info.

1-Do I have to use a side by side magnet assembly as he did or can I use a single row of really strong magnets on each side? Can I use a 3 x 1 x 1/2 instead of side by side 3 x 1/2 x 1/4 essentially combining the side by side magnets?

2-Will the use of thicker magnets make it more efficient? For example, Will a 3 x 1 x 1 increase efficiency over a 3 x 1 x 1/2?

3-Can someone explain the orientation of the magnets by poles...IE pos to pos and neg to neg with the magnets pushing away from each other?

4-On this site:
Applied Magnets & WindMax Wind Turbines

most magnets are described as 'magnetized through thickness'. Is this what I need?

I have already made corrigated ribbons using his proceedure for my 5" ribbon tweeters and they sound and measure better than the originals.

I will post pictures and results as I proceed.

Thanks.

[tinitus]

Originally Posted by SpinMonster

most magnets are described as 'magnetized through thickness'. Is this what I need?

from two construction pictures, I would say yes, magged through thickness

[tinitus]

Originally Posted by SpinMonster

3-Can someone explain the orientation of the magnets by poles...IE pos to pos and neg to neg with the magnets pushing away from each other?

I have marked north and south poles in the picture

I suppose its how it should be

[tinitus]

Originally Posted by SpinMonster

Will the use of thicker magnets make it more efficient? For example, Will a 3 x 1 x 1 increase efficiency over a 3 x 1 x 1/2?

it will be more efficient, yes

Dahlberg's magnets looks like 2" x 1/2" x 1/4"
so the only magnets you should use are 2" x 1/2" x 1/2"
ofcourse they can be longer
but may get so strong they are difficult to handle

note that each side of the magnet system should be assembled to one unit before placing the magnets
though Dahlberg seem to use a neat trick, so that he can rotate each side, to ease the mounting of magnets
but I can tell, be very very careful here
they will clash together at any chance given, and with exstreme force
but could be a very dangerous trick
make no mistake, or your fingers could be crushed, completely beyond saving
it is a very dangerous thing

and even if using very thick and strong iron, the force of the magnets will bend it
hence notice the small brass tubes Dahlberg is using

I will estimate that the combined magnet force could lift a small car

[tinitus]

note that increased sensitivity may not be linear
the result is not always better sound
sometimes it just gets more peaked

[SpinMonster]

Thanks for the responses.

It appears that he used a dual magnet configuration to make the magnets more manageable. The pulling force on some of the alternative sizes approach 70lb's. I guess smaller mags and more of them will also resist breaking too.

[brunob]

I always wear safety goggles and gloves when dealing with neodymium magnets.

[brunob]

Originally Posted by SpinMonster

I wish to build a 26-36" ribbon like the one here:

"The tall neodymium ribbon". Part 1

Is there any measurements of the frequency response and sensitivity available for "The tall neodymium ribbon". I did not see any on the website - may be I have missed it?


Bruno

[ABJensen]

Originally Posted by brunob

Is there any measurements of the frequency response and sensitivity available for "The tall neodymium ribbon". I did not see any on the website - may be I have missed it?


Bruno

DahlbergAudioDesign

[SpinMonster]

Looks usable from 500 up. I wonder how efficient that one is. Coupled with two free air 12's it should be a pretty good system.

It looks like a 26" would do fine on top end.