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Thread: RAAL vs. Beryllium Dome

  1. #11
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    Mar 2011
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    Default Re: RAAL vs. Beryllium Dome

    My experience with the beryllium and also the inverted Focals I owned in the past always presented a too bright of sound as if my listening distance wasn't within their target range. That's the way i can put it to words, they were just too "hot" and almost couldn't stretch their legs. I also experimented a bunch with the inverted Focal woven products and those tweets were too mellow for my taste but off axis was good from what I can remember. Those mid 90's are hard to remember...

    Those Infinity Emits were always nice, pleasant, and composed sounding. Almost a refined soft sound. The RAAL's by far have presented the finest clarity and resolution, imo. Almost as if the RAAL products are in a different level. Love them!

  2. #12
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    Oct 2010
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    St George UT & Glenwood Springs CO
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    Default Re: RAAL vs. Beryllium Dome

    I think that Tweeters can come down to personal preference. I had Beryllium domes in my Usher Tiny Dancers, and Circular ribbons in 3 different Genesis speakers..

    I have the Stock Nrt tweeters in my Towers.

    The standard for me is "Silver Bells" from the Mannheim Steam Roller album "Christmas Extraordinaire". The Genesis ribbons, and the Usher Be dome really nailed the shimmering bells.

    However for long listening periods, each tweeter would eventually give me "Ear Burn", something my Nrts don't do.

    Blutarsky

  3. #13
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    Default Re: RAAL vs. Beryllium Dome

    Quote Originally Posted by GirgleMirt View Post
    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.

    Quote Originally Posted by GirgleMirt View Post
    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.
    -Jacob

  4. #14
    Join Date
    Nov 2010
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    Default Re: RAAL vs. Beryllium Dome

    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

  5. #15
    Join Date
    Nov 2009
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    243

    Default Re: RAAL vs. Beryllium Dome

    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.

  6. #16
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    Default Re: RAAL vs. Beryllium Dome

    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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    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  7. #17
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    Default Re: RAAL vs. Beryllium Dome

    Quote Originally Posted by RicardoJoa View Post
    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.
    Ricardo,

    you are 100% correct. The added extension of the RAAL ribbon is really just a bonus and competitors often uses this to say things like, "Well, you can't hear past 20kHz anyway"... As I had once documented, the key aspect of the ribbon performance is the exceedingly fast decay times that are not just fast, but nearly perfectly uniform -- which indicates minimal stored energy.

    In other tweeter designs, different frequencies create different amounts of stored energy such that a 6kHz signal might linger a bit longer past the initial impulse than a 4kHz signal. With the Raal's, frequencies decay almost instantly and with great uniformity. This is precisely what gives it such tremendous detail while also sounding so delicate and non-fatiguing, like there is no tweeter and the highs just materialize in the air.... They also exhibit an incredible polar response.

    The added extension is not the key performance benefit...
    .
    .
    .
    Good Sound To You!

    David Fabrikant
    www.ascendacoustics.com

  8. #18
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    Default Re: RAAL vs. Beryllium Dome

    You don't get that kind of technical info from many speaker companies...if any.
    -curtis

  9. #19
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    Nov 2011
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    Default Re: RAAL vs. Beryllium Dome

    Ditto what curtis said. I had to read through Dave's posts twice to absorb all of that. This is going right into my "archive bookmarks" for future reference.

    I'm continually blown away by Ascend's commitment to excellence. Now if you'll excuse me, I'm going to digest all of this for the rest of tonight.


    Thank you, Dave. This post was incredibly useful and informative.
    -Jacob

  10. #20
    Join Date
    Nov 2005
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    496

    Default Re: RAAL vs. Beryllium Dome

    well after Dave's post this is somewhat useless but since it's typed...

    Quote Originally Posted by Dark Ranger View Post
    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.
    I think that's just the thing... You can find some measurements of a multitude of tweeters and drivers on Zaphaudio. There's an Usher Be tweeter here, he notes:

    to date I've seen no real proof that any beryllium usage, either pure or heavily alloyed with other materials, is any better than aluminum or coated fabric. There's certainly a lot more to a tweeter than the chosen diaphragm material.
    Hehe I don't want to sound like a broken record, but what is so special about Be tweeters? Is there really an advantage to 'Be' besides for marketing? Wilson use Titanium, Dynaudio soft dome, Thiel aluminum, etc... I don't think 'Be' is really that special for tweeter material... Some of the top 'high end' and very highly regarded tweeters are 'plain' soft dome!

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