DR: Nice post!

I've stumbled on a very interesting conversation on that RAAL ribbon, which, besides knowing of them as sort of the very expensive holy grail of ribbons before Ascend talked of them, ...

Ok let me just preface with this. For some reason, maybe it's a lack of golden ears or experience/exposure, I've always been 'fine' with ultra high end tweeters. For example, the tweets in the JMLabs Utopia, in the Dynaudio Confidence series, in the B&Ws Nautilus/800 series, in Wilson Audios, etc., all sound fine to me... They're most often the least of my complaints. I've read some complaints about such tweeters, but I guess I'm just not that sensitive to them, and find complaints about them a bit weird. That said, I've also heard a couple of ribbons in Verity audio, ProAcs, MBL, PSB, Aurum Camtus, etc... And as the metal/soft dome featured in the flagship products of most company, also found most of them very very good, and yeah sure in some case did definitely notice a significant difference between these tweeter types, it wasn't as I had been struck by lighting and thought I could never listen to a dome tweeter ever again... It was enough to intrigue me though, and I decided going for a ribbon in my next speakers

Having finally 'taken delivery' of the ribbon speaker, my dome vs ribbon experience didn't really translate to the Sierra NrT tweeter vs Fountek NeoCD3.0. Or maybe it did as I was satisfied with both tweeters, but didn't find these two sounded significantly different... Maybe the Fountek isn't that great for a ribbon, maybe the NrT is very good, maybe I simply suck at "the listening" but IMHO, they're both good tweeters and as such, don't sound that different...

The RAAL is a different beast though, and looking up more info on it, I stumbled on an interesting discussion. But before, even before David/Ascend ever talked about the RAAL ribbon, I had heard of that name and heard this was a special tweeter. Very expensive, but as I had heard, one of the best and almost in a class of its own. (Maybe I even heard it but I can't recall..) Now, finally, to the interesting RAAL discussion, discussing out of all things, David F.'s measurements of the said tweeter! http://techtalk.parts-express.com/sh...e-RAAL-70-20XR Very interesting discussion! Some quotes from it:

Quote Originally Posted by Ryan
I was impressed by the RAAL when I heard it. Though, it was probably the most expensive tweeter on display that day, and I've only had one other experience where I _really_ got to listen to a $200+ dome. I would like to hear the RAAL back to back against a similarly well implemented very expensive dome tweeter. I trust Pete's ears, but.... trust but verify.


Just to stir the pot, it is interesting to read some of DavidF's comments in that thread w/ regards to the RAAL:

*RAAL ribbon tweeter upgrade will add $350 for each speaker. This price is expected to increase significantly once our current supply runs out.
I will say this in advance, I was surprised at the results – this particular RAAL ribbon tweeter is as close to a near perfect high frequency transducer as I can imagine. More specifically, I honestly can’t imagine that I will ever have the privilege of measuring anything better. Forget reading subjective descriptions of it… I have documented it in detailed measurements
While the ribbon is indeed objectively superior, many listeners still prefer the sound of the NrT. So much depends on your source material and your own preferences -- it is very subjective.
And this is where things can get dangerous No, you certainly do not need better electronics. However, the ribbon is extremely revealing and about as high resolution as a transducer can get. It will more easily reveal lesser electronics than a dome tweeter.
GirgleMirt note: Hmmm... Maybe it could be my source/electronics too?
Going with the ribbons is a very expensive option and while the differences are audible, that difference is probably not worth the expense for most of our customers.
I believe for loud and dynamic home theater, most rock and hip hop -- the NrT will probably be preferred.
I kind of cherry picked some choice quotes, but shocking to read from a guy trying to upsell a $700 option. I had Ascend speakers prior to my DIY days. I always liked DavidF. I thought he was a real straight shooter.
EM

This I think sums up my thoughts on the matter, after the NrT upgrade, another tweeter upgrade, this one probably more expensive than the NrT upgrade, just wouldn't rock my world... I'd most probably skip it as I'm perfectly fine with the top end performance of the NrTs, and wouldn't invest hundreds of $ at this time for a 'marginal' upgrade... But that's me, the 'tweeter sounds fine' guy! A woofer or 3 way upgrade, probably would be more tempting as a mid/bass improvement would imho be more doable or significant than improving the top end...

But reading the thread; RAAL vs Fountek:
This is like comparing an RS28F to an Aircirc. Both are fantastic but it's not just two versions of the same thing, even though it's similar technology, there's still differences that two or three graphs alone won't show but other graphs should. Or is an RS28F as good as a Beryllium Aircirc?

One such example i've seen is people who compare Dennis Murphy's Philharmonic 1s (fountek neocd3, SB 8") with his Phil 3s (RAAL 70-10d, SS Revelator 8") - so far they've all said that while the differences in bass/lower midrange are minimal, but the differences in tweeters are well worth it, and so they consider the Phil 2s (RAAL 70-10d, SB 8") to be the optimal choice dollar for dollar.
Anyhow, I guess more reading and more listening in my case is required!

to sum up, you and I both admit that the RAAL test better from a dispersion standpoint, and a linearity standpoint (response). From a non-linear standpoint, the RAAL 70-10 and 2.0 have a similar overall cutoff frequency before THD exceeds 1% (~2500Hz). However, above that frequency, the RAAL has lower overall distortion, even though both are predominantly 2nd order. The MUCH lower moving mass of the ribbon element in the 70-10 simply does more, with less, and exhibits a more realistic presentation to the ears. I don't care if both of them were $10 each. I'd still take the 70-10 over the 2.0 every time. They just sound better. It does suck that they are expensive due to being hand made and tested. But they are amazingly consistent.
Not sure whether the Fountek '2' they're talking about is the Neo X or Neo CD models, but anyway, again, RAAL, costing about 3-4x as much as Founteks, are found to be better

But anyhow, it all depends on application too as they mention... To my ears, the Founteks sound great, and the NrTs surely don't sound like mushy jello or tin cans compared to them... Some random notes/quotes on the Fountek and it's selection criteria in the design I went with:

The extended range of the W4-1337SA's enabled a high tweeter crossover point, and an easy cross to a ribbon tweeter. The Fountek NeoCd3.0 seemed like a great choice. All the drivers exhibit high marks for value, which gives this design a high performance to cost ratio.
The top end had to have realistic reproduction of triangles and cymbals while extracting the ambiance of the recording venue.
...
The only tweeter considered for the project was the Fountek NeoCD3.0. It fit perfectly in the over all design goals and the extended frequency response of the W4 allowed the ribbon to be crossed at a high enough frequency to minimize distortion. A perfect match!
Treble: Cymbals sound like cymbals and the sound of triangles float in the air. Love or hate ribbons but they do a better job of realistically reproducing the highs to my ears than any other type of tweeter. The highs are open and airy with great off axis dispersion.
Treble, well, I love ribbons so it's a hands down winner in that respect for me.
IMHO, as stated, the Fountek is <100$ and probably not the best ribbon tweeter on earth, but it's definitely no slouch. As for the NrT, I don't know exactly how it would compare to an AirCirc, 7000, Crescendo, etc., but to my ears, it does a really good job, which in the end is quite similar to the Fountek NeoCD3.0...

But for tweeter upgrade, going from the quote of Dave's quotes on RAAL vs NrT, makes me doubt a little more the tweeter upgrade... Well I don't know, guess we'll just have to see!