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Hello to all,
I just wanted to post this thread to show the benefits of different tweeters, dome, planar, folded and true ribbons. I in no way have any intention to to cause any negatives or positives for either configurations just info about tweeters and why I am excited about the A5 and it's price point with the planar magnetic tweeters and what some other tweeters actually cost.
Hi Guys,
I have to share this with you… I have extensive experience with different diaphragm materials and have evaluated at least a half dozen Be dome tweeters. From pure Be to various composite materials such as BeCu2 (Copper Beryllium alloy) and AlBeMet (Aluminum Beryllium alloy). I have even evaluated the different forming mechanisms from vapor deposited to film.
Back in Sept 2009 (prior to the development of our NrT) we started consulting with Brush Wellman in an effort to develop our own vapor deposited pure Be dome diaphragm (just the dome itself) to retrofit the Sierra-1 tweeter. At that same time, we also started working with a Japanese company (TSK) to develop our very own Be dome tweeter. I believe the Japanese were the first to ever use Be in a transducer (an old Yamaha speaker although it could have been Pioneer)
After spending so much time evaluating, the only Be dome that offered a measurable advantage over a Titanium dome was vapor deposited pure Be. The advantage being that due to the very high stiffness to mass ratio, the resonance frequency of the dome was pushed into the 30 kHz range and out of human audibility. This meant that we now have a dome tweeter with the crispness and “shrill†of a metal dome but without the ringing issues which cause the ever common fatigue issues of metal domes.
In my professional opinion, there is absolutely no comparison between the very best Be dome tweeter and the RAAL ribbon tweeter. None, Zero, Nada :0
When trying to accurately reproduce such small wavelengths, the less moving mass the better. The moving mass should have as close to zero stored energy as possible and must be able to start and stop instantly. The problem with a dome tweeter is that in order to make the dome move, a voice coil (wire windings) must be attached to the diaphragm. This adds a significant amount of moving mass (which includes the wire windings, adhesives and the former) which creates stored energy, excess inertia and dramatically increases decay times. For every wavelength produced, the dome and the windings (adhesives and former as well) need to move with the diaphragm. BTW, this issue exists for planar dynamic ribbons and folded ribbons.
A pure ribbon tweeter works differently… there is no voice coil, no windings, no former. An electrical current runs through the diaphragm itself (the ribbon) which is suspended between very powerful magnets. There is no excess moving mass, the only moving part is the radiating area itself…
For example, the moving mass of the RAAL ribbon we are using is a mere 0.039 grams with a radiating area of 13.6 sq cm. This weighs about the same as a single voice coil winding, and most quality tweeters have a dozen or more windings. For comparison purposes, the Scan Speak pure Be dome (66400) has a moving mass of 0.35 grams (which is great for a dome tweeter) with a radiating area of 7 square cm (1 inch dome). Our RAAL has twice the radiating area with ten times less moving mass!
There really is no comparison; the RAAL has better high frequency extension, significantly better transient response, much less stored energy and a better horizontal polar response. BTW, the SS 66400 retail for $510 each.
No dome (regardless of diaphragm material), planar dynamic ribbon or folded ribbon will compare favorably against our RAAL pure ribbon. The only possible way to get less moving mass is the legendary plasma tweeter. In what is now fast approaching 30 years of transducer evaluations, no tweeter I have ever measured has come close to the RAAL ribbons… It really comes down to the simple physics of the different designs.
Hope you all find this useful!
__________________
I just wanted to post this thread to show the benefits of different tweeters, dome, planar, folded and true ribbons. I in no way have any intention to to cause any negatives or positives for either configurations just info about tweeters and why I am excited about the A5 and it's price point with the planar magnetic tweeters and what some other tweeters actually cost.
Hi Guys,
I have to share this with you… I have extensive experience with different diaphragm materials and have evaluated at least a half dozen Be dome tweeters. From pure Be to various composite materials such as BeCu2 (Copper Beryllium alloy) and AlBeMet (Aluminum Beryllium alloy). I have even evaluated the different forming mechanisms from vapor deposited to film.
Back in Sept 2009 (prior to the development of our NrT) we started consulting with Brush Wellman in an effort to develop our own vapor deposited pure Be dome diaphragm (just the dome itself) to retrofit the Sierra-1 tweeter. At that same time, we also started working with a Japanese company (TSK) to develop our very own Be dome tweeter. I believe the Japanese were the first to ever use Be in a transducer (an old Yamaha speaker although it could have been Pioneer)
After spending so much time evaluating, the only Be dome that offered a measurable advantage over a Titanium dome was vapor deposited pure Be. The advantage being that due to the very high stiffness to mass ratio, the resonance frequency of the dome was pushed into the 30 kHz range and out of human audibility. This meant that we now have a dome tweeter with the crispness and “shrill†of a metal dome but without the ringing issues which cause the ever common fatigue issues of metal domes.
In my professional opinion, there is absolutely no comparison between the very best Be dome tweeter and the RAAL ribbon tweeter. None, Zero, Nada :0
When trying to accurately reproduce such small wavelengths, the less moving mass the better. The moving mass should have as close to zero stored energy as possible and must be able to start and stop instantly. The problem with a dome tweeter is that in order to make the dome move, a voice coil (wire windings) must be attached to the diaphragm. This adds a significant amount of moving mass (which includes the wire windings, adhesives and the former) which creates stored energy, excess inertia and dramatically increases decay times. For every wavelength produced, the dome and the windings (adhesives and former as well) need to move with the diaphragm. BTW, this issue exists for planar dynamic ribbons and folded ribbons.
A pure ribbon tweeter works differently… there is no voice coil, no windings, no former. An electrical current runs through the diaphragm itself (the ribbon) which is suspended between very powerful magnets. There is no excess moving mass, the only moving part is the radiating area itself…
For example, the moving mass of the RAAL ribbon we are using is a mere 0.039 grams with a radiating area of 13.6 sq cm. This weighs about the same as a single voice coil winding, and most quality tweeters have a dozen or more windings. For comparison purposes, the Scan Speak pure Be dome (66400) has a moving mass of 0.35 grams (which is great for a dome tweeter) with a radiating area of 7 square cm (1 inch dome). Our RAAL has twice the radiating area with ten times less moving mass!
There really is no comparison; the RAAL has better high frequency extension, significantly better transient response, much less stored energy and a better horizontal polar response. BTW, the SS 66400 retail for $510 each.
No dome (regardless of diaphragm material), planar dynamic ribbon or folded ribbon will compare favorably against our RAAL pure ribbon. The only possible way to get less moving mass is the legendary plasma tweeter. In what is now fast approaching 30 years of transducer evaluations, no tweeter I have ever measured has come close to the RAAL ribbons… It really comes down to the simple physics of the different designs.
Hope you all find this useful!
__________________
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