ATC have built their own tweeter in the last five years. Previously they used Excel and before that Vifa and before that Audax (40+ years of pro audio)
It took many years years to develop and they regard Excel tweeters as extremely good - so improving upon that was difficult.
The ATC dome tweeter looks much like any fabric dome tweeter however it has NO Ferrofluid and had to be made with extremely tight tolerances in order to dissipate heat (large ATC are intended to play at realistic levels of real instruments like a drum set). A dual spider was necessary to avoid rocking motion which is a challenge in all dome tweeters due to their small size and why the majority use Ferrofluid.
Ferrofluid is not bad but it does dry out with time and changes the response and eventual reliability.
ATC like doped fabric domes and pulp paper or constrained layer damping type approaches to cones or domes. This is because these materials are intrinsically damped and therefore do not "ring" or affect the timbre of the sound reproduced as much as rigid materials. (Of course break up can be issue with softer materials and therefore expensive motors and large voice coils are needed which makes the transducer units overall extremely costly)
I am not sure if it will ever be made available to the general market and other speaker manufacturers like other ATC drivers.
It took many years years to develop and they regard Excel tweeters as extremely good - so improving upon that was difficult.
The ATC dome tweeter looks much like any fabric dome tweeter however it has NO Ferrofluid and had to be made with extremely tight tolerances in order to dissipate heat (large ATC are intended to play at realistic levels of real instruments like a drum set). A dual spider was necessary to avoid rocking motion which is a challenge in all dome tweeters due to their small size and why the majority use Ferrofluid.
Ferrofluid is not bad but it does dry out with time and changes the response and eventual reliability.
ATC like doped fabric domes and pulp paper or constrained layer damping type approaches to cones or domes. This is because these materials are intrinsically damped and therefore do not "ring" or affect the timbre of the sound reproduced as much as rigid materials. (Of course break up can be issue with softer materials and therefore expensive motors and large voice coils are needed which makes the transducer units overall extremely costly)
I am not sure if it will ever be made available to the general market and other speaker manufacturers like other ATC drivers.