RAAL vs. Beryllium Dome

[Dark Ranger]

btw, just to be clear.. I wasn't implying it was a marketing decision... Merely that their recent popularity probably influenced customer to ask for ribbon tweeter, which could have also influenced decision to research & implement it.. (performance of course being critical)

Ah, I think I see your point now. I'm not sure how the ribbon option came up, that might be something for me to research in the forums later. Still, I'm very glad Dave chose to offer it in the Towers/Horizon.

Guess what I was trying to say in last post is that there are a lor of options... So why ask for be in particular? Think critical is: 1) price/performance ratio 2) off axis performance (and sensitivity, FR, etc.). Is be that much better than NrT to warrant few hundreds for be? What are the best advantages of be tweet over soft dome for instance?

That is a good question for the OP, although it might come down to simple curiosity. Beryllium is pretty exotic stuff and doesn't show up too much in "regular" speakers. Maybe the performance benefits of a Be tweeter do not outweigh the cost below a certain price point. Ascend has never been a "let's use the most expensive stuff just because we can" kind of company. From an objective standpoint, I'd be very interested to learn how the popular Be-based tweeters stand up against the 70-20XR where it matters. Similarly, I'd be very curious how the popular Be-based tweeters stand up against the NrT.

Oh, and one more thing: if Dave released a Be-based tweeter upgrade and believed it would give us reasonable improvements considering the cost, I would be inclined to buy it. Take the Sierra-1/NrT upgrade thread going on here. As an example in pure speculation, let's say he offered a Be tweet upgrade. Provided he could show us measurable data and his subjective listening feedback (which I trust, since my taste in loudspeakers brought me to Ascend in the first place), then you bet I'd go for it.

[Jeff52]

Thank you Jacob for the very informative post, I really appreciate honesty over hype, I to trust Dave and as you said "since my tastes in loudspeakers brought me to Ascend in the first place". That's why I'm here and have an all Ascend loudspeaker setup. I'm real close to being able to upgrade to the ST's but undecided with my old ears if they deserve the RAAL's over the NrT's. That's for another thread though, my intentions are to thank you my friend.
Best regards, Jeff

[RicardoJoa]

well i dont think any of us would be to fully enjoy raal extreme extension, but i think there is is more to it then just FR. The raal version is flatter, and also with imevements in decay time. i think is where it make it worth it. If i get the tower i would go straight raal, simply there isnt anything close in the market at this price.
The only thing that is holding me is because im from abroad and it will cost too much to take advantage of the 30 money back, if i happen not to fit my liking.

[davef]

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!

[Jeff52]

So Dave, what am I supposed to do with my 340's 27mm soft dome tweets with all that mass that has to be moved 12+ windings and the energy it takes to do so now that you convinced me of the superiority of the RAAL at 0.039 g's and radiating area of 13.6 sq cm.???
Take care my friend, Jeff Nordi

[Dark Ranger]

I'm real close to being able to upgrade to the ST's but undecided with my old ears if they deserve the RAAL's over the NrT's.

So Dave, what am I supposed to do with my 340's 27mm soft dome tweets with all that mass that has to be moved 12+ windings and the energy it takes to do so now that you convinced me of the superiority of the RAAL at 0.039 g's and radiating area of 13.6 sq cm.???

This is definitely the most important decision you'll ever make.

I haven't heard the 340s yet, but if they're like Ascend's other products, they perform well above their price point. The RAALs are in a completely different class, though. Kinda like the difference between a fast and agile sports car compared to a Formula 1 car.

[Jeff52]

This is definitely the most important decision you'll ever make.

I haven't heard the 340s yet, but if they're like Ascend's other products, they perform well above their price point. The RAALs are in a completely different class, though. Kinda like the difference between a fast and agile sports car compared to a Formula 1 car.

I hear you
I love the 340's, and yes they do perform well above their price point, they replaced Athena F2's and I never looked back, I actually gave the F2's to friend. I used the 170 as mains for awhile to compare with the 340's, very similar sound but just a lot more of it and they dig deep for their size. The only problem is now I want a faster more agile machine, sports car or formula 1 ?

[davef]

So Dave, what am I supposed to do with my 340's 27mm soft dome tweets with all that mass that has to be moved 12+ windings and the energy it takes to do so now that you convinced me of the superiority of the RAAL at 0.039 g's and radiating area of 13.6 sq cm.???
Take care my friend, Jeff Nordi

-- Hi Jeff,

No worries... and I should make this clear to everyone. Without question, the RAAL ribbons are technically superior transducers when it comes to accuracy. However, this does not mean that they will sound better to you.

For example, a good customer of ours came by with his lovely wife this afternoon to audition both the ribbon towers and the NrT towers. He already owns Sierra-1 NrT.

He liked the ribbons and spent perhaps an hour listening to them. We then swapped out the ribbon towers with the NrT towers and they listened for 2 1/2 hours, goosebumps and everything. They went home with a pair of black bamboo NrT towers as this was a sound they were more familiar with and preferred compared to the ribbon versions.

Even with the technical superiority of our ribbons, it still comes down to what sounds best to you, and your 340's use an exceptional dome tweeter

[Jeff52]

-- Hi Jeff,

No worries... and I should make this clear to everyone. Without question, the RAAL ribbons are technically superior transducers when it comes to accuracy. However, this does not mean that they will sound better to you.

For example, a good customer of ours came by with his lovely wife this afternoon to audition both the ribbon towers and the NrT towers. He already owns Sierra-1 NrT.

He liked the ribbons and spent perhaps an hour listening to them. We then swapped out the ribbon towers with the NrT towers and they listened for 2 1/2 hours, goosebumps and everything. They went home with a pair of black bamboo NrT towers as this was a sound they were more familiar with and preferred compared to the ribbon versions.

Even with the technical superiority of our ribbons, it still comes down to what sounds best to you, and your 340's use an exceptional dome tweeter

Thanks Dave, I needed to hear that, and yes the 340 tweeter is excellent even below and above ear level. I've never heard a pure ribbon and I know I will be very happy when the time comes to order the NrT ST's.
Cheers Jeff

[pawsman]

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!

Dave,

I read the Ascend Board even though I own a competing brand of speaker (Selah Audio Verita, which has the RAAL 70-20XR ribbon). This is the first time I've seen the RAAL ribbon compared to the Scanspeak Beryllium dome. It was a very enlightening comparison and confirms my thinking that the RAAL ribbon is simply the best tweeter I've heard. You hear very extended, natural highs without the aggressiveness, resonances or artifacts that most Domes typically have. Thank you for providing the analysis-

pawsman