@shadorne
Completely ignoring the point and instead demonstrating some odd ideology that isn't mat-sci. The notable aspect about Stereophile measurement is the result is system based, which I do not know if the Seas is the same and can not be compared. What does it mean? The decay energy being seen isn't just from the tweeter, but the interactions being produced by the system. This includes the mid driver, which the review states wasn't well isolated and was the source to the decay energy seen here. In order to have a clean plot, obviously the driver needs come to a rest as quickly and cleanly as possible. Energy that isn't well damped through the basket, the interface between the basket and the baffle, the baffle, behind the driver, and from other drivers will show in the plot. So your in a system and the diaphragm material plays a part, but in this test, its demonstrated to be more than itself as being the cause of the delayed decay.
Now where a well damped diaphragm material has its advantage is when you do happen to hit a resonance in the operating range, the material itself will reduce the level through internal damping. As you pointed on the Focal tests, the Ti driver performance wasn't good but the Be is better. Did you even note that Ti has much better internal dampening than Al or Be? So it isn't the material selection in this case, but issues with the system instead. Any material can be tripped by poor design. Use a material, work within its constraint, and spend a greater effort in design over material selection.
As for the Kef, I believe that small notch in the treble may have something to do with the tangerine wave guide they use. Seems to be a solution compromise to the fairly wide and even dispersion in the upper treble. A number of speakers fall off to the sides, which make room balance a slight bit more of an effort to get right. If you look at the dispersion of it, the Reference 5, or the Blade 2, they all exhibit the same trait and treble radiation smoothness. Though right above 16khz, the sound field has less smoothing and is the point were we see that notch. They even use somewhat differing materials as the upper series use a Al-Li-Mg alloy. My guess is being the mathematical point in its physical design of that wave guide as its highly linear.
Completely ignoring the point and instead demonstrating some odd ideology that isn't mat-sci. The notable aspect about Stereophile measurement is the result is system based, which I do not know if the Seas is the same and can not be compared. What does it mean? The decay energy being seen isn't just from the tweeter, but the interactions being produced by the system. This includes the mid driver, which the review states wasn't well isolated and was the source to the decay energy seen here. In order to have a clean plot, obviously the driver needs come to a rest as quickly and cleanly as possible. Energy that isn't well damped through the basket, the interface between the basket and the baffle, the baffle, behind the driver, and from other drivers will show in the plot. So your in a system and the diaphragm material plays a part, but in this test, its demonstrated to be more than itself as being the cause of the delayed decay.
Now where a well damped diaphragm material has its advantage is when you do happen to hit a resonance in the operating range, the material itself will reduce the level through internal damping. As you pointed on the Focal tests, the Ti driver performance wasn't good but the Be is better. Did you even note that Ti has much better internal dampening than Al or Be? So it isn't the material selection in this case, but issues with the system instead. Any material can be tripped by poor design. Use a material, work within its constraint, and spend a greater effort in design over material selection.
As for the Kef, I believe that small notch in the treble may have something to do with the tangerine wave guide they use. Seems to be a solution compromise to the fairly wide and even dispersion in the upper treble. A number of speakers fall off to the sides, which make room balance a slight bit more of an effort to get right. If you look at the dispersion of it, the Reference 5, or the Blade 2, they all exhibit the same trait and treble radiation smoothness. Though right above 16khz, the sound field has less smoothing and is the point were we see that notch. They even use somewhat differing materials as the upper series use a Al-Li-Mg alloy. My guess is being the mathematical point in its physical design of that wave guide as its highly linear.
