Their ribbons are very deep in the driver, alone the (narrow) opening does not allow a wide dispersion.
If the AMTs were that good in dispersion, they would surely show measurements and praise them for that.
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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.
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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.
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.
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Exactly. Everyone would use these drivers, they would be an absolute must-have for every speaker shop.
lowmass;5820764A said:
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).
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:
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.
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
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
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:
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
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
That reduces the spl of the same ammount as the attenuation. Unless you go active, that reduces the range of possibe mid-bass drivers immensely.
That makes the suspension very difficult since the ribbon can't suspend itself anymore. That's also the reason why the Elac 4 Pi is only a supertweeter, it can't be used to reproduce sound below 10k. You also get problems with the back radiated sound.
Or shade magnetic field
That's not so easy. On the edge, where two magnets of different power meet, the magnetic field is inhomogene. It also does not work on AMTs which got the folds vertically.
I have zero interest in debating your theory to years of actual experience. You do know this is why you've been banned from other forums don't you?
Seeking some advice on tweeter substitution from the experienced.
I have been running Aurum Cantus G3 ribbon tweeters for years.
After hearing some good Be tweeters and compression tweeters like Radian 475PB, I believe I prefer treble that has more leading edge presence, density, and sparkling clarity than Aurum Cantus G3 ribbon provides.
I have briefly heard Raal ribbons at various venues, but I don't think Raal ribbons are the answer to my quest, either. It may be partly due to my age-related high-frequency loss also, but ribbons seem too ethereal and soft in texture in treble to me. Radian 475PB sounds very clear and exciting, so if I can't find something better, I may stay with it, crossed over at 1kHz at 18dB slope via active crossover.
Which of the following would provide what I am seeking over Aurum Cantus G3 ribbons?
AurumAST25120 by drjlo2, on Flickr
ESSamt1 by drjlo2, on FlickrMy G3 specs
AurumG3 by drjlo2, on Flickr- Status
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