apparently the same thing !
Hi Rex
RobH and I went through this a while back in one of the older forums ( lost in one of the crashes ) - they are apparently the same thing - just a different marketing name. I'll let Rob expand on that info if there is more to it. JBL uses "Polyplas" also , though I don't know where it fits in the scheme of things.
What is it ? I always thought it was a thick, paint-on , goopy, water-borne plastic ( if correct, making it a cousin of latex paint ) . Seems that JBL has maybe trademarked use of the name, though I've seen old Altec references to it - used on their old horns ( multicells or the 311 - maybe the first generation of MantaRays ).
Here's a link to Piedmont Plastics that doesn't seem to support my water-soluable contention. Their Aqua-plas is PVC based .
In addition to being added to the usual woofer suspects, JBL has a light "dusting" of it on the 2450SL titanium, 4" diaphragm ( plus the 275nd - 1.75" & 435Be - 3" diaphragms ). If it's a newer K2 speaker - you'll find judicious use of this dampening compound in the transducers moving parts. The dome weight of the 2450SL is 75% titanium with 25% plastic - so the literature suggests. For the last 7 weeks I've been listening to a pair of the 2450Sl diaphragms ( in 2440 motors ) and this coating/mixture does make a difference to the dampening characteristics of the 4" diaphragms resonances. I can't decide if I prefer it to Altecs' nicely damped 288 aluminum diaphragms. This JBL does have more HF extension. But, that's a different story .
regards <> Earl K