I haven't made any impedance for quite some time. I have been mostly interested in relative measurement when I did do them as per above.
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Maybe a really dumb question. but is it possible instead of using bars for front and rear pole pieces can you just drill several holes into a metal plate of around 4-5 mm thick ? instead of cnc a nice pocket? since i cant mill steel 🙁 but i can drill it 🙂
i was just simulating some amt's just for fun, and i might try to make a tiny one for ***** and giggles 🙂
or are we gettign some weird effects around the holes in the gap?
got some 40x20x5 mm neo's from the rubanoide project left, i know it is not gone be as massive as yours, since i can only make pleats of max 4mm with these magnets. but its worth a try 🙂
by the way you probable already seen it but this is a nice source of information i must say https://www.youtube.com/watch?v=frt1kudMc_M they are not shy of using the silicone adhesive everywhere 🙂
i was just simulating some amt's just for fun, and i might try to make a tiny one for ***** and giggles 🙂
or are we gettign some weird effects around the holes in the gap?
got some 40x20x5 mm neo's from the rubanoide project left, i know it is not gone be as massive as yours, since i can only make pleats of max 4mm with these magnets. but its worth a try 🙂
by the way you probable already seen it but this is a nice source of information i must say https://www.youtube.com/watch?v=frt1kudMc_M they are not shy of using the silicone adhesive everywhere 🙂
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With a solid plate you'll get a much less concentrated field intensity in the gap.
There are also fringe effects that makes the field intensity non-linear.
Using plates makes it a lot harder to assemble the motor; adding the back pole plate would be a nightmare.
But perhaps there's a smart way of placing the holes in order to get a more linear SPL over the frequency range. That would require quite some 3D simulations though.
More likely only 3 mm or even less.
Yes, I have.
To use several foil strips is always an option and most certainly needed for a tweeter as the length is short.
Also, as it seems like the membrane is rather stiff, it is feasible to do so in the Adam's case; the fold's movement will be small and behave as one section.
I don't think it is beneficial for a full range AMT though, it is better to adjust the resistance with the width of the foil strip having the length.
Also, dividing the fold's side into several section might be tricky and may behave non linear depending on the excursion.
| is the alu strip, ( and ) are the softer carrier.
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Thanks for your awnsers !
is'nt the limit of the max dept the accuracy of the maker i mean a 4mm wide should be able to fit in a 5mm gap ? (in theory) or does it widen when played hard?
yeah i was afraid the holes in the plate will do some weird stuff. and i cant simm it in femm... 🙁 one thing though why is it hard to put on the backplate is sliding not an option. or does it force it away? wich indeed would make stuff harder 🙂
so looks like rods are the save way to go. witch is tobad since putting on 2 plates i believe is faster then glueing 40 rods.
what rods do you use now ? i thought of using 5mmx5mm, i noticed you used 3x10 in the beginning, but if i simm 10mm the field sucks (for my setup). if i used 4mm (in the direction femm let us simm it as a solid plate of 1000mm) i got the best field, but bars dont come that small 🙁 smallest i could find in the end was 5x5 or 4x6 etc.
Thanks.
The membrane moves to and fro along the z axis because of the air that is jettisoned and thus giving the membrane a push in the opposite direction.
Try to make a model of an inverted motor.
It always easier to add a little thing to the larger.
Why such a hurry? BTW, the back pole pieces aren't glued. That way I can easily change and/or adjust the membrane.
I've sent you the femm files I've made so far. Hopefully are the file names self explanatory.
Thanks allot !
that about the jetting is something i did not thought about at all 🙂 nice. i've seen your inverted motor somewhere in page 4 5 clever!. but for a perforated plate its gone be a bit more difficult 🙂
Well i wrestled with the runanoid it has 8 of these magnets between 2 bars, i just slides the second bar on top of the bar where the magnets where glued to. It was pretty doable. and when i think of it ofcourse it does not push it away 🙂 silly me since i did it 8 times already with these rubanoids.
You hit the nail on its head... why such a hurry 🙂 this might be a downfall of being me. 🙂 i admire your determination and if i may say so slow but steady approach allot! it worked wonders so far! i think i never worked on a project that long 🙂 (it is not criticism!!)
thanks allot for the femm files. i will take a look especially to the inverted part to see if i can translate it to a something that resembles a perf plate.
one thing i though of yesterday night at 4 o clock 🙂 (cant sleep when i read al this interesting stuff just before i go to bed) is it possible to add very small wedges to the steel bars >? like triangle of a non magnetic material. so you wont disturb the modeled field and get the reflections out instead of inside the gap. of course the angle of the triangle need to be right so it wont reflect to the bar above it(or beneath). and this might be a waste of magnetic gap, i dont know. but i recon you need less damping foam if you can guide all the reflections out?
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aha but this is only for the sides ? i meant on the bars. just my 2 cents but i can imagine allot of reflecting against all those bars as well ? i believe you tried rounding somewhere along the way? but that also messes with you field i can imagine.
there is allot of steel blocking the air that wants to come out, i thought guiding it might help a bit in soem distortion regions/peaks and dips
must admit is labor intensive to aplly such thing to every strip , nothing for me so it seems 😉
there is allot of steel blocking the air that wants to come out, i thought guiding it might help a bit in soem distortion regions/peaks and dips
must admit is labor intensive to aplly such thing to every strip , nothing for me so it seems 😉
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The back pole pieces are beveled in order to reduce the otherwise reflected back wave to the front.
It doesn't take much time to do it. Let's say 1 minute a piece.
The front pole pieces are NOT beveled. I don't want the turmoil of the compression that would then otherwise occur between the pole pieces.
I will however in my next looooong AMT, add one extra millimeter between the pole pieces. But that is really due to other reasons.
It doesn't take much time to do it. Let's say 1 minute a piece.
The front pole pieces are NOT beveled. I don't want the turmoil of the compression that would then otherwise occur between the pole pieces.
I will however in my next looooong AMT, add one extra millimeter between the pole pieces. But that is really due to other reasons.
ah ok, yeah i noticed al the plate version have rather large pockets, and verry few pieces of steel hanging in front of the membrane. this might be because they are all closed back .... i dont know. (i dont know how the inner backplate looks like if it even has oen, i assume they do)
Are you referring to the Adam Tweeter in the video?
Well, that is a tweeter and I think that is a much easier target.
I made a tool from 2 heatsinks from a PC.
https://plus.google.com/u/0/115027702649442747143/posts/N7DUh3pxgBP?pid=6099333653141874402&oid=115027702649442747143
There is a lot of pics from my amt's
Bernt
https://plus.google.com/u/0/115027702649442747143/posts/N7DUh3pxgBP?pid=6099333653141874402&oid=115027702649442747143
There is a lot of pics from my amt's
Bernt
That's right!
Don't forget to study the master aka båndsei if you're into doing your own AMT, Wrinex.
very nice foto doc! i was in the progress in rereading you amt thread as wel bandsei, but its pretty hard without the pictures 🙁
By the way, you know what the blue foil was micron alu micron pet? and if i may ask is it possible to maybe buy some from you ? you where very generous to send me a roll, and now i got my printer up and running it is very very useful so far. i wondered if you could spare some more. ofc i would be happy to pay for it and of course the shipping costs this time 🙂
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