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KEF Blade 2 vs Ascend ELX Towers as End Game
- Thread starter sneabs
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And now, vertical dispersion, where there is a much bigger difference between the ribbon and the dome.
Ribbon:
Dome:
Not only that but to my eyes it seems like the titan tower measures slightly more neutral with the much smoother directivity. It's puzzling that Dave and so many others have claimed the ribbon version sounds better, it really makes you wonder if there is sighted bias at play. This would be an interesting experiment to have people compare them blind to see if their impressions change.
Generally speaking, I prefer our ELX towers to be placed a bit closer to the front wall. We optimized the positioning for the KEF's based on what position measured best for them. Once that was determined, we positioned our ELX next to them in a typical AB-AB setup. Both speakers were/are high passed at 80Hz and with an F12 subwoofer in play, not just the KEF's (we don't have the ability to do direct A/B comparisons with one set of speakers high passed and the other set not high passed). Regardless, as impressive as the deep bass is for the Blades, still not close to an excellent quality, properly positioned subwoofer.
Also, we give listeners the option of being blind, but so far - none have chosen this. These are very low-pressure informal listening sessions - not a shootout, just an opportunity for anyone to come and listen to some wonderful performing speakers, different - but yet similar.
So far, and as predicted by many - preference really comes down to the song and differing dispersion characteristics and that has been my experience as well.
I wish the others who have listened would post their thoughts, but I am not the type of person to pressure anyone since this is really about having some fun, hanging out, and taking a break from the daily grind. The Blade 2 meta's are fantastic speakers and when things here slow down, I hope to just sit down and fully enjoy them for many hours (no comparisons, no critical listening - just enjoyment)
No sighted bias, we have had hundreds of direct comparisons between our ELX Ribbon Towers and ELX Titan Towers (dome tweeter). Results are remarkably consistent, 8 out of 10 prefer the 70-20xram ribbons. And this consistency is fully evident in comparing our ELX Titan against the Blade 2 and ELX Ribbon against the blade 2. It can't be denied.
There is still more to learn about what we hear than is being captured by NFS measurements, we are always getting closer though. I have even done comparative listening outside, which is nearly all direct sound so directivity isn't nearly as much as a factor - it became even easier to hear differences between the 70-20xram and even some of the best dome tweeters available. There is a character to the 70-20xram, an overall smoothness with more precise attack and decay that is very evident once you start to notice it. Not everyone hears this though, and - like the results of these various comparisons, it completely depends on the music being listened to.
This is incorrect. The ribbon tweeter we are using has significantly faster decay times than any dome tweeter, meaning there is much less stored energy compared to a dome tweeter. If you are referring to side-wall reflections causing additional reverb, that also isn't correct - our listening room for these sessions is heavily treated on the side-walls and the horizontal dispersion width of the RAAL 70-20xram is only marginally wider than our Titan tweeter.
I believe the differences in what is heard comes down to the complete lack of stored energy (which is why there is a clearly audible difference in attack and decay) as well as significantly less vertical reflections (with our ribbon) compared to a dome.
I understand that but you didn't clarify if these direct comparisons were blind, if they weren't I'm not sure how it can be claimed no bias is present. I mean the fact that it's a ribbon, an upgrade and more expensive are all very feasible reasons why people would be biased into thinking the ribbon is better than the dome.
Because we have done many blind comparisons between our ELX Titan Towers and ELX Ribbon Towers... The differences in what you can hear, once you recognize it, are quite evident. Come visit, have a listen... Also read the other summaries on our forum.
Start with this one, and his follow-up posts below this one. This is not one of our customers, he own's Kef's. Note, during this listening session they only compared the Blades to our ELX Ribbon Towers.
Please do not misunderstand me, I am not saying which is the "better" speaker - far from it. There are just some very interesting and unique differences between all 3 speakers that are being compared. These types of comparisons encourage me to dig deeper than standard measurements to try and determine how to better capture (by measurement) what listeners are hearing. I just wish there were more hours in the day and I had more energy
‘Stored’ energy in a tweeter?
Keith
Keith
Ricardojoa
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Are you saying tweeters dont have stored energy or they have? Im pretty sure you are more knowledgeable than many of us here.
This exact topic came up years ago in the what science shows thread on AVS and Dr. Toole himself responded with a few different quotes regarding ribbons: Here is a question/comment from someone:
Question:
Right, but frequency response graphs don't usually tell the whole story. That's why Dave Fabrikant displays measurements such as Impulse Response, Energy Time Curve, and Cumulative Spectral Decay for his Sierra Towers: http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend Sierra Ribbon Tower.pdf
These can help reveal differences between, for example, dome and ribbon tweeters.
Dr. Toole response:
The time domain differences I see are correlated with frequency response irregularities, as is expected. Transducers are minimum-phase devices and the time domain performance can be calculated from the amplitude vs. frequency response. Waterfalls and the like add no new information, just different perspectives on the same information. Note that prolonged ringing in waterfalls always starts at a peak in the frequency response. Note also that the waterfall does not start declining at t=0. It should if properly windowed.
Further, there is persuasive evidence that humans do not hear the ringing. Our perceptions are dominated by spectral cues.
Toole, F. E. and Olive, S.E. (1988). “The modification of timbre by resonances: perception and measurement”, J. Audio Eng. Soc., 36, pp. 122-142.
This is not saying that the speaker at issue is inferior, just that the portrayal of performance is not balanced. There are much better dome tweeters.
Another comment from Dr. Toole about ribbons:
It is interesting that one of the first loudspeakers I tested in the anechoic chamber at the NRCC in 1967 (52 years ago!!!!) was a ribbon tweeter, the Kelly Ribbon from the UK. I just looked at the measurements in my personal archive. At the time it was promoted for the same reasons that ribbons and electrostatic loudspeakers are today: "massless" diaphragms, "Instant" transient response, etc. etc. It was a learning experience for me, and only definitively provable in double-blind listening tests. Of course, nothing back then was as good as things are now, but the implied superiority simply was not heard. As time passed and measurements and knowledge improved, nothing has changed. There are good loudspeakers and not-so-good loudspeakers, and the method of moving the air has not revealed itself as being the dominant factor. If any one method was obviously superior, it would dominate the products we can buy.
As far as the "massless" consideration is concerned, I have a Tesla S P90D in my garage that accelerates from 0-60 mph in 3.2 s. It is a heavy four door, potentially 7-passenger, sedan that is much quicker than most two seat sports cars - and I have owned a few. The secret is in the motor, and that is also the relevant factor in loudspeaker transducers. Ribbons and electrostatic speakers typically have relatively weak motors compared to what can be put behind a cone or dome. In the end, frequency response is king.
So this is kind of what I basing my opinion on that if the ribbon ELX truly does beat the titan dome in a properly controlled blind listening test, it would be interesting to figure out why because I'm not seeing anything in the measurements that would point to that.
Question:
Right, but frequency response graphs don't usually tell the whole story. That's why Dave Fabrikant displays measurements such as Impulse Response, Energy Time Curve, and Cumulative Spectral Decay for his Sierra Towers: http://www.ascendacoustics.com/pages/products/speakers/SRT/Ascend Sierra Ribbon Tower.pdf
These can help reveal differences between, for example, dome and ribbon tweeters.
Dr. Toole response:
The time domain differences I see are correlated with frequency response irregularities, as is expected. Transducers are minimum-phase devices and the time domain performance can be calculated from the amplitude vs. frequency response. Waterfalls and the like add no new information, just different perspectives on the same information. Note that prolonged ringing in waterfalls always starts at a peak in the frequency response. Note also that the waterfall does not start declining at t=0. It should if properly windowed.
Further, there is persuasive evidence that humans do not hear the ringing. Our perceptions are dominated by spectral cues.
Toole, F. E. and Olive, S.E. (1988). “The modification of timbre by resonances: perception and measurement”, J. Audio Eng. Soc., 36, pp. 122-142.
This is not saying that the speaker at issue is inferior, just that the portrayal of performance is not balanced. There are much better dome tweeters.
Another comment from Dr. Toole about ribbons:
It is interesting that one of the first loudspeakers I tested in the anechoic chamber at the NRCC in 1967 (52 years ago!!!!) was a ribbon tweeter, the Kelly Ribbon from the UK. I just looked at the measurements in my personal archive. At the time it was promoted for the same reasons that ribbons and electrostatic loudspeakers are today: "massless" diaphragms, "Instant" transient response, etc. etc. It was a learning experience for me, and only definitively provable in double-blind listening tests. Of course, nothing back then was as good as things are now, but the implied superiority simply was not heard. As time passed and measurements and knowledge improved, nothing has changed. There are good loudspeakers and not-so-good loudspeakers, and the method of moving the air has not revealed itself as being the dominant factor. If any one method was obviously superior, it would dominate the products we can buy.
As far as the "massless" consideration is concerned, I have a Tesla S P90D in my garage that accelerates from 0-60 mph in 3.2 s. It is a heavy four door, potentially 7-passenger, sedan that is much quicker than most two seat sports cars - and I have owned a few. The secret is in the motor, and that is also the relevant factor in loudspeaker transducers. Ribbons and electrostatic speakers typically have relatively weak motors compared to what can be put behind a cone or dome. In the end, frequency response is king.
So this is kind of what I basing my opinion on that if the ribbon ELX truly does beat the titan dome in a properly controlled blind listening test, it would be interesting to figure out why because I'm not seeing anything in the measurements that would point to that.
It's a question I often ask myself when I listen to the ELX setup. Obviously the somewhat unique combination of generally wider dispersion vs typical domes (the Titan is likely wider than most) in concert with a tighter vertical window contributes. I don't know whether the objectively faster transient response of a "massless" ribbon translates to audibility in any meaningful way. I've also heard my share of other ribbon speakers and none have sounded like the EXL does, so the overall design, driver selection/integration, and crossover engineering all make their contributions to the overall listening experience. And for me, the differences in sound are totally obvious, no blind listening is required to prove that they exist. Blind testing these against other high-performance speakers for preference, however, would be very interesting.
I'm fairly certain Dave at Ascend has much more knowledge than any of us here as well,but for some reason his knowledge gets questioned because he sells the actual product he designs and develops.
Ricardojoa
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Well but Purited is asking about tweeter in general not a particular product from ascend. So are you saying only tweeter sold from ascend have stored energy and the rest of the tweeters used from other manufacturers dont have stored energy or perhaps it does?
Keith_W
Master Contributor
The answer is rather complicated, but i'll summarize. All mass-spring systems have stored energy, but tweeters typically dissipate the energy much faster than woofers.
The decay of stored energy depends on the system's Q (damping), where lower Q = faster decay. Total Q (Qts) depends on the Thiele-Small parameters Qms (mechanical damping), Qes (electromagnetic damping).
Qms is affected by the compliance of the suspension and the mass of the cone. Tweeters have to move faster than woofers and have a lower excursion range, which means low mass diaphragms and stiffer suspensions, so they ring more. But they have a much lower Qes since the voice coil gap is much smaller than woofers, which means the BL (force factor) is much higher. Overall the Qts is lower, so tweeters ring less.
But ... for the sake of argument, suppose you take a tweeter and woofer with the same Qts, and let's say both of them ring for 5 cycles. For the tweeter, 5 cycles of 10kHz = 0.1ms. For the woofer, 5 cycles of 100Hz = 10ms. You can see that even though both of them have the exact same amount of ringing, the woofer rings for much longer.
I believe all this is correct, but it has been a long time since I read Vance Dickason's book. Will gratefully accept corrections if I am wrong.
Ricardojoa
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So tweeters do have stored energy. Different types of tweeters are going to have different level of stored energy. Thank you
Yes, in the mechanical side and electrical side. A dome tweeter is a mass-spring system, for all mass-spring systems - there exists a moving mass and a restorative force (the suspension). All mass-spring systems have stored energy, this can be seen on the impedance measurement of any dome tweeter (or woofer) by way of the resonant peak (Fs). That resonant peak is the energy of the moving mass equaling the energy of the restorative force (there is basically no damping at this frequency so there is full undamped movement), which represents the release of stored energy.
On the electrical side, the "force" - this is the voice coil wound around a former. This is an inductor - by definition, an inductor stores and releases energy.
A true ribbon tweeter is not a true mass-spring system, the moving mass is the conductor itself (the force), there is, technically, no restoring "spring" other than that same conductor and air itself. You will not see a resonant peak on the impedance measurement of a true ribbon tweeter. This is different than AMT, planar or "leaf" tweeters. In addition, the moving mass of a true ribbon tweeter is typically at least 1/50th of the moving mass of a dome.
This is all easily verifiable by way of impedance measurement, impulse response, but likely the easiest way to see this is by way of CSD. I had published a a bunch of measurements showing these comparisons maybe about 15-20 years ago, but I can't seem to find it since we redid our website and forum.
Luckily, there is Google's wayback machine:
I believe this is why both the attack and decay sound more distinct and defined on true ribbon tweeters (at least with RAAL, been a decade since I listened to a non-RAAL true ribbon tweeter, but I wouldn't expect greatly differing results). It is also fairly easy to hear this with acoustic guitar, piano, cymbals once you recognize it and the recording is of high quality.
I know many will have a differing opinion regarding this, and that is OK - but the one thing I can assure anyone of is that there is very likely no person who has done more investigative work on this or has more experience in these comparisons than I do. Frankly, I would love to not offer the RAAL 70-20xram as an option as these tweeters are incredibly expensive and with the now unbelievably high tariffs on imports from Serbia, the RAAL 70-20xram is practically priced out of reach. However, our demos continue and the large majority continue to prefer the 70-20 (sighted or not-sighted) over any other option.
You beat me to it!
Ricardojoa
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What is wrong with people asking opinions on this forum about two different speakers ? How is your whining consider sustainable. Don’t like it, move over!
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You are viewing this thread as self-promoting? Do you not understand we had nothing at all to do with this comparison? Ascend clones? what are you even talking about? Do you honestly think the OP or anyone in this thread is employed by us or encouraged by us?
I'll think twice before posting here again...
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