Now we are getting to the wacky bits.
Doping of the cone to attenuate the higher frequencies usually involves spraying with plastidip, various amounts of contact adhesive (bison kit) or other known to work products (on paper cones). Blu tack is pretty wacky but my use of it is nothing new, plenty of others have done it before with good results.
I got to thinking about up firing drivers and other ways of attenuating the higher frequencies. As it is facing upwards and gravity does it's thing then why does the doping have to actually stick to cone ? How about this .........................
I must say i laughed aloud when the thought first popped in my head. I have surpassed myself again. I crumbled up a piece of polystyrene sheet in to the small balls and put it on the cone of my new 5.25" driver. It has had an effect and maybe the answer to all my prayers
It weighs bugger all, doesn't stick to the cone and does attenuate the higher frequencies. It's quite fun when a loud bass noise comes along watching the beads jump up and down like popping popcorn. Only problem is containing it. If the driver was mounted from the inside of the cabinet then a piece of grille cloth over the top on the outside of the cab would do the trick.
Amazing
It does a few things that i really wanted to persevere with. It keeps all the motion of the bass producing drivers in phase with the floor as the Doc would say. Also it keeps more to the semi omni spirit and the acoustic centre of the drivers are more or less the same distance from my ears. If i double up the number of 5 inchers the acoustic centres wont be able to stay as is. In a simple semi omni design like the nva cubes then the tweeter is always a fair bit closer to the ears than the up firing mid bass and is never a problem. Maybe i am obsessing about this when i shouldn't.
