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Old 1st July 2013, 08:28 AM   #201
solhaga is offline solhaga  Sweden
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Quote:
Originally Posted by Rewind View Post
So since your speaker is much larger, maybe you should try a large baffle around it.
Currently I´m pursuing a better hf response so the baffle size is not significant
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Old 1st July 2013, 08:30 AM   #202
solhaga is offline solhaga  Sweden
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Quote:
Originally Posted by Rewind View Post
What would happen with 2um alu foil? I have a lot of leftovers from a ribbon mic project. Impossible to handle though. The foil with a pealable paperback would save me a weekend of swearing.
A 2 um foil will mean a too high resistance, around 16 ohm. And, as you said, it is impossible to handle.
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Old 1st July 2013, 08:39 AM   #203
Rewind is offline Rewind  Sweden
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I never found the link to the foil with peelable paperback?
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Old 1st July 2013, 08:43 AM   #204
solhaga is offline solhaga  Sweden
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Made a membrane with 8/2 folding ratio and 5/5 alu ratio, approximately 4 ohms (blue with a wave guide):

Click the image to open in full size.

Still no better hf response although lf response was extended.
I guess the depth of the folds, 8 mm, turns out to be a Helmholtz resonator.
If that is the case, next try with 6/2 folding ratio (that is, 6 mm deep pocket) and 4/4 alu ratio will show a better hf response.
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Old 1st July 2013, 09:04 AM   #205
solhaga is offline solhaga  Sweden
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Quote:
Originally Posted by Rewind View Post
I never found the link to the foil with peelable paperback?
These types of foil can be found in Denmark and Norway as "frokostfolie".
One type (rul-let) with 7 um alu has a paperback that can be removed by water and another (Vita) with 10 um alu has a peelable paperback.

Look for them in super markets.
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Old 1st July 2013, 09:11 AM   #206
Rewind is offline Rewind  Sweden
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Quote:
Originally Posted by solhaga View Post
These types of foil can be found in Denmark and Norway as "frokostfolie".
One type (rul-let) with 7 um alu has a paperback that can be removed by water and another (Vita) with 10 um alu has a peelable paperback.

Look for them in super markets.
Doh. I was looking for them in India. I guess 7um is preferred? Which membrane won your shootout? I guess there is still no clear winner since you are making new designs still.
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Old 1st July 2013, 10:24 AM   #207
Rewind is offline Rewind  Sweden
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Quote:
Originally Posted by RayCtech View Post
If you use a waveguide instead of EQ you will improve the fidelity as the distortion will be much lower. And the directivity and soundstage improves also...
Picture shows the first prototype with AMT "midrange" and AMT "super tweeter" in a CNCed Corian waveguide, and three 8" drivers in a combined CNCed Corian baffle / basket..

Click the image to open in full size.
I compaired homemade waveguides for the TPL-150. I prefer a straight wall, using 15cm wide wooden planks, instead of a waveguide based on the curvature of the Avantgarde Trio smallest horn, that is similar to yours. I angled the curved walls more open than the Trio horn. I used the same waveguide for a 50cm true ribbon, that is better at frequencies 5000Hz and up, and here the curved waveguide works better.

Last edited by Rewind; 1st July 2013 at 10:39 AM.
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Old 1st July 2013, 12:15 PM   #208
Rewind is offline Rewind  Sweden
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Quote:
Originally Posted by solhaga View Post
Currently I´m pursuing a better hf response so the baffle size is not significant
I don't like the TPL-150 above 10kHz anyway. Maybe you should consider True Ribbons crossed at 3-5kHz? Much lighter membrane and produces HF perfectly.
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Old 1st July 2013, 12:35 PM   #209
Rewind is offline Rewind  Sweden
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I remembered something from my ribbon mic project. Someone wrote that they treated their aluminum foil first by gently hammering out imperfections, using a cloth as protection on top of it. It did not really work with 2 micrometer foil, but worked great with kitchen foil. That did not matter since kitchen foil was too thick for ribbon microphones but it is not for speakers. It may improve sound slightly.

Last edited by Rewind; 1st July 2013 at 12:41 PM.
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Old 1st July 2013, 06:02 PM   #210
solhaga is offline solhaga  Sweden
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Originally Posted by Rewind View Post
Doh. I was looking for them in India. I guess 7um is preferred? Which membrane won your shootout? I guess there is still no clear winner since you are making new designs still.
Yes, the 7 um is the winner. But one has to take great care when cutting.
The angle of the knife is crucial, wrong angle and you have ripped instead of cutted.
The paper on 7 um is also more easy to get rid off, just soak it in water.
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