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Old 28th August 2012, 03:31 AM   #11
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Location: Fairfield, IA
Quote:
Originally Posted by båndsei View Post
[IMG]Click the image to open in full size.[/IMG]
Here is mesurement at 40cm.distance.
Distortion increaces below 1.1khz.Mesurement is limited at 500hz. 48db.

Bernt.
Nice work! I like the way it looks, especially on your omni type speakers. The measurements look very good also. Have you been able to quantify the sensitivity at 2.83V?
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Old 28th August 2012, 05:04 PM   #12
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It´s a prefabricated diaphragme and th with of the strips all the same.
The magnetic field is different from the one used for ribbons.
[IMG]Click the image to open in full size.[/IMG]
The magnetic lines does not cross the gap,I hope the picture helps.
Resistance is 7.2 ohm.

Bernt
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Old 28th August 2012, 05:38 PM   #13
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[IMG]Click the image to open in full size.[/IMG]
This shows Aurasound NSW2 2" unit and my diy Amt.
Recorded at same level and settings.It is messured at 40cm.distance.Amt is a dipole and level should be compared at 2-3m. distance.
Aurasound has a sensivity of 84db, 1w. 1m. 1000hz.

Bernt.

Last edited by båndsei; 28th August 2012 at 05:41 PM.
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Old 28th August 2012, 06:08 PM   #14
solhaga is offline solhaga  Sweden
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Location: Värsta Götaland
Quote:
Originally Posted by båndsei View Post
It´s a prefabricated diaphragme and th with of the strips all the same.
The magnetic field is different from the one used for ribbons.
[IMG]Click the image to open in full size.[/IMG]
The magnetic lines does not cross the gap,I hope the picture helps.
Resistance is 7.2 ohm.

Bernt
Yes, it would seem that the flux is even in the y-plane at any given point in the x-plane, at least for any practical excursion. That's really great

If you have access to the strip's terminals you could have the outermost strips, the ones in the strongest flux, coupled in parallell.
I don't know how many strips there are, but let's say the pattern can be 3 3 2 2 1 1 1 1 2 2 3 3 to get an even force along the diaphragme.
You would still be above 4 ohms?
But perhaps the diaphragme is rigid enough, so it doesn't flex as it moves in the field.
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Old 8th September 2012, 09:59 AM   #15
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Here is a nude model!!
[IMG]Click the image to open in full size.[/IMG]
My latest one.It performs almost like the ones with "horn"
[IMG]Click the image to open in full size.[/IMG]
Mesurements with and without "horn"
I can´t make changes to the wiring of the diaphragm as it is bought from ESS Heill amt.
Bernt

Last edited by båndsei; 8th September 2012 at 10:08 AM.
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Old 8th September 2012, 04:49 PM   #16
solhaga is offline solhaga  Sweden
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Location: Värsta Götaland
Quite interesting setup. I'm sure the sound stage is great.
Have you considered moving somewhat away from the corner?
In my setup the ribbons are 1,5 meters from the back and 1 meter from the side wall.
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Old 11th September 2012, 04:16 PM   #17
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My room is only 3 meters wide,and i use it for TV as well,so I must make compromises.

Bernt
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Old 13th September 2012, 08:20 PM   #18
paulfx is offline paulfx  United States
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Location: Cary, NC, USA
Default Side Flux AMT

Nice!
I love the way it eliminates diffraction from a diaphragm that is usually buried under iron prongs. From the other comments on this thread, more consistent output from each diaphragm pleat could be had if we could flow less current through the outers and more through the inners. To do that would require constructing the diaphragm. Could the resistance of each conductive strip vary with the flux levels shown in the graph, so each pleat has about the same loudness?
By the way, Neil Davis has written in Audio Amateur magazine on the topic of putting together custom AMT diaphragms. Calling Mr. Davis?
Also by the way, we have an Lgrau from Denmark here on diyAudio. Gentlemen?
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Old 13th September 2012, 09:05 PM   #19
solhaga is offline solhaga  Sweden
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Location: Värsta Götaland
Quote:
Originally Posted by paulfx View Post
..Could the resistance of each conductive strip vary with the flux levels shown in the graph, so each pleat has about the same loudness?..
Perhaps we are saying the same thing, but if the strips are in series, the same current will flow in each strip no matter its individual resistance.
A wider strip means less current density and thus maybe the same force to the diaphragm in a higher flux as a narrow strip in a lower flux.

I was also wondering if there are any DIY AMTs out there.
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Old 15th September 2012, 02:30 PM   #20
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Here even more nude.
[IMG]Click the image to open in full size.[/IMG]
And seen from the top.
[IMG]Click the image to open in full size.[/IMG]
I have the same thought´s:can i improve the design?I don´t think i can.I would like to go deeper,but i think all have been tried, as it is what everyone wants.
It performs perfect and messures good too.

Bernt
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