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Multi-Way Conventional loudspeakers with crossovers

Why not the Aurum Cantus AST25120?
Why not the Aurum Cantus AST25120?
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Old 12th June 2019, 06:54 AM   #21
ICG is online now ICG  Germany
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Originally Posted by Zvu View Post
You could be right or it could be very poor QC. Aurum Cantus is no exception to that mater.
Okay, if the quality spreads that much, it's a very good reason not to buy the Daytons. Even the low price is no excuse for that.

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Originally Posted by Zvu View Post
Baaming of AMT tweeter of that lenght isn't negotiable. It is a matter of physics. Or you will provide us with measurements that will prove ICG wrong ?
Exactly. The only explaination would be if the hearing (upper frequency limit) would be impaired (but I wouldn't suggest he can't hear that anymore).
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Old 12th June 2019, 07:00 AM   #22
ICG is online now ICG  Germany
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Originally Posted by Defo View Post
Aurum Cantus seems to have traditional ribbons (such as the G1) that do beam, and "Aero Striction" ones, that does not. Apparently.
Their ribbons are very deep in the driver, alone the (narrow) opening does not allow a wide dispersion.

Why not the Aurum Cantus AST25120?-g2-g3-jpg

If the AMTs were that good in dispersion, they would surely show measurements and praise them for that.
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Old 12th June 2019, 08:36 AM   #23
mandoman is offline mandoman  Australia
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Quote:
I'm sorry but I don't buy that.
You don't believe me. Buy one and find out for yourself. They do not beam vertically like a traditional ribbon, period. Chalk and cheese. It is really very very obvious if you have a ribbon to compare it with. Side by side I had them, and I am not deaf to high frequencies. It was astonishingly obvious the difference. I could not believe it myself when I first fired it up, but the microphone backed up my ears, and I am not the only one claiming the AC AST do not beam vertically. How they do it I have no clue.

Last edited by mandoman; 12th June 2019 at 08:44 AM.
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Old 12th June 2019, 10:52 AM   #24
lowmass is offline lowmass  United States
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Sometimes with a ribbon, if there is a peak in response between 5 and 10kHz the beaming effect can be precieved as exagerated. How carfully was the test conducted? each driver leveled in response etc?

If they dont beam then they have accomplished something no one has been able to do and believe me they have tried. I would think they would be all over this phenom in the press. And I would think many of us here would have heard of this.

I very much want to see measurments that show this dispersion but certainly not buying one to find out. Every planermagnetic and ribbon driver I have ever built shows the same beaming for size.

Another way to help with beaming is to shade the array. could be done with much stronger magnet forces in mid section of driver with lower strength magnet forces as you get twards ends, BUT this has not proven to be a big help within practical constructions.

I believe some are simply blocking off some of the diaphragm to held but again not a big usefull difference without a fair amount of compermise elsewhere.

Last edited by lowmass; 12th June 2019 at 10:56 AM.
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Old 12th June 2019, 11:08 AM   #25
ICG is online now ICG  Germany
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Originally Posted by lowmass View Post
If they dont beam then they have accomplished something no one has been able to do and believe me they have tried. I would think they would be all over this phenom in the press. And I would think many of us here would have heard of this.

I very much want to see measurments that show this dispersion but certainly not buying one to find out. Every planermagnetic and ribbon driver I have ever built shows the same beaming for size.
Exactly. Everyone would use these drivers, they would be an absolute must-have for every speaker shop.

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Originally Posted by lowmass;5820764A
nother way to help with beaming is to shade the array. could be done with much stronger magnet forces in mid section of driver with lower strength magnet forces as you get twards ends, BUT this has not proven to be a big help within practical constructions.
That won't work on an AMT because the folds had to expand differently, depending on the position, that would introduce very high non-linear distortions. They had to chop the membrane into shorter pieces (which isn't the case).
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Old 12th June 2019, 07:38 PM   #26
Patrick Bateman is offline Patrick Bateman  United States
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Originally Posted by mandoman View Post
You don't believe me. Buy one and find out for yourself. They do not beam vertically like a traditional ribbon, period. Chalk and cheese. It is really very very obvious if you have a ribbon to compare it with. Side by side I had them, and I am not deaf to high frequencies. It was astonishingly obvious the difference. I could not believe it myself when I first fired it up, but the microphone backed up my ears, and I am not the only one claiming the AC AST do not beam vertically. How they do it I have no clue.
Wavefront shape of a ribbon is dictated by diaphragm shape of a ribbon, and a tall narrow ribbon will have a narrow vertical beam. It is inescapable.

There are only two ways to widen the vertical beamwidth of a tall narrow ribbon:

Click the image to open in full size.

You can do it acoustically, by using foam or felt to attenuate the high frequencies radiated at the top and the bottom

OR

You can physically curve the ribbon.

That's it.
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Old 12th June 2019, 08:30 PM   #27
jholtz is offline jholtz  United States
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The simplest solution to minimize a narrow vertical dispersion with AMT's and ribbons is to use shorter ribbons or shorter AMT's. Curt and I have used Fountek CD3.0's in our Statements series and a AST2560 in our Bordeaux design.

Both will have very broad horizontal dispersion with similar vertical dispersion when compared to a one inch dome. Both are awesome for seated listening and very nice for walk around casual listening at normal distances. No head in the vise effect.

I would suggest anyone buying AC AST drivers plan on measuring them carefully for FR. The AST2560's we used in the development Bordeaux (mine) was an older driver that measured extremely close to published FR graphs by Aurum Cantus. However sometime in early 2017 a production change was made which altered FR and caused a broad dip in response. That is why Curt introduced a revised crossover with the help of the builder who noticed it and took measurements. This isn't a lack of quality control just bad management by AC for not updating the documentation.

BTW, anyone who buys a Bordeaux parts kit from Meniscus will get in house measured AST2560's to ensure the correct crossover goes with it.

HTH

Jim
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Old 13th June 2019, 12:58 AM   #28
Flaesh is offline Flaesh  Russian Federation
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Quote:
Originally Posted by Patrick Bateman View Post
Wavefront shape of a ribbon is dictated by diaphragm shape of a ribbon, and a tall narrow ribbon will have a narrow vertical beam. It is inescapable.

There are only two ways to widen the vertical beamwidth of a tall narrow ribbon:

Click the image to open in full size.

You can do it acoustically, by using foam or felt to attenuate the high frequencies radiated at the top and the bottom

OR

You can physically curve the ribbon.

That's it.
Or shade magnetic field
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Old 13th June 2019, 01:44 AM   #29
Pallas is offline Pallas  Pakistan
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Quote:
Originally Posted by jholtz View Post
The simplest solution to minimize a narrow vertical dispersion with AMT's and ribbons is to use shorter ribbons or shorter AMT's. Curt and I have used Fountek CD3.0's in our Statements series and a AST2560 in our Bordeaux design.

Both will have...similar vertical dispersion when compared to a one inch dome.
I suppose that depends on what one means by "similar." However, I would not use that word here.

Quote:
Originally Posted by jholtz View Post
Both are awesome for seated listening and very nice for walk around casual listening at normal distances. No head in the vise effect.
That is certainly not the case with your Statements design, which I have heard. It is also not the case with the latest Adam studio monitors, which I have also heard.
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Old 13th June 2019, 02:03 AM   #30
jholtz is offline jholtz  United States
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Originally Posted by Pallas View Post
I suppose that depends on what one means by "similar." However, I would not use that word here.

That is certainly not the case with your Statements design, which I have heard. It is also not the case with the latest Adam studio monitors, which I have also heard.
Interesting. That makes you one in well over 2000 pair built that didn't agree. There are lots of other designs. I hope you find the one that fits you.

Best regards,

Jim
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