Diy AMT

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As I read it both 15 and 10 my 7mm models has a lower output at higher frequency.
I should have measured at exactly same conditions.
A 10mm deep version with 15my mylar is its way.
Low freq output is better on the 15 my 7mm than on the 7mm 10my version ,listening fullrange.

Bernt
 
As I read it both 15 and 10 my 7mm models has a lower output at higher frequency.
I should have measured at exactly same conditions.
A 10mm deep version with 15my mylar is its way.
Low freq output is better on the 15 my 7mm than on the 7mm 10my version ,listening fullrange.

Bernt

Listening Fullrange.

Now that I like.

Depending on your music, it could actually work.

Acoustic guitar would be pretty awesome.

Lute.

Same family I guess.
 
Solhaga

I think they are more sensitive than the ones with only one coil.
I have measured at random voltage and variable resistance.
I will investigate if double coil makes better sensitivity.
My next measurement of 10mm deep and 15my mylar will be with 2,8v at 1meter too.

Bernt
 
You are right Wrinex.
I usually measure off axis becourse i listen to them off axis.
But i have to measure at the same conditions to compare them.
Next time....

Bernt

yeah thats ok :) i know the drill. setting up so much stuff doing measurements again and again, with one motor but different membranes is quite a bit of work all together.

every now and then i tell myself , now we gone do some proper measurements of all the candidates to have nice comparisons. but then a new idea comes along and it changes all that :( although you have some measurements that are able to compare with one an another.

measurements from 1 meter would change allot to. i recon the low end will drop several dB, so this could dictate the max spl if you where to smooth the top end out. a bit of baffle would help but it wont recover to a 30cm measurement. 30cm does give a better look into the distortion if you dont want to annoy the neighbors with very very loud sweeps :) haha

Very interesting everything as always ! looking forward to the rest!
 
All diaphragms are 10x32mm 15my mylar 40my alu 2 coil.
90x32x9mm_15my_mylar_40my_alu.PNG
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9mm deep
All measurements at 1meter 2,8v.
90x32x9mm_15my_40my_1m_2_8v_on_axis_.jpg
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9mm deep on axis
90x32x9mm_15my_40my_1m_2_8v_off_axis.jpg
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9mm off axis
90x32x7mm_15my_40my_1m_2_8v_on_axis.jpg
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7mm on axis
90x32x7mm_15my_40my_1m_2_8v_off_axis.jpg
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7mm off axis.
Resistance is app 1,6 ohm.
Comments? or missing measurements?

Bernt
 
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It is measured like this:
DSC03078.JPG
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Not my strongest field, it is the "double Kithara" but a strong open field.
I did not calculate it, but yes.
Seems that 7mm 15my mylar is best.
Have to compare with my "old" 80x32x6,5 10my alu 12my mylar single coil.I think it has same resistance.
DSC03077.JPG
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My latest diaphragms ,and the ESS Heil on the right side.

Bernt
 
Comments.

Very nice.

One point to mention in your testing. And an easy one to change.

Your scale on the left side is in 10 db per division.

If you changed the scale to 5 db per division it would be much easier to compare with other measurements.

And it will actually look much smoother!

Awesome performance in an AMT!

:up: :up:

it would look less smooth.. why do you think commercial data uses 5 or 10 db instead of 1 2 3 or 4 :) it will indeed be much more easy to read thats true :)
 
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If the measurements were taken in a larger and higher room the driver could be located farther away from reflective walls and similar objects. This would also make for a much smoother graph.

But it is doing the same thing every time that is most important. We can figure out some of the response just by seeing the measurement location and the microphone location.

And the wooden sides that the driver is is would help a bit more in shaping the response if there were a top and bottom piece to.
 
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