I just think i did it right choosing the shack forum, after a year or so reading anonymous in diy forums.
Mike It should have been this way around with the sub, and i am glad to hear it, as larger objects are brought into resonance like windows and with this sub the walls and even the larger of all the mother earth under you yourself.
I know i should have posted that in a new thread but I found today something that worries me though, it is about the little brother of this one – the Maelstrom 18”, please take a look at that, the guy complains he bottoms it out easily when playing frequencies 20 to 30Hz
The link http://www.hometheatershack.com/forums/exodus-audio/20266-7-6-cu-ft-maelstrom-x-18-build-9.html
And my comment on that issue was:
Dudes, on the bottoming out the sub ..
I have dayton reference sub Dayton RSS265HF-4 (and I know how this noise is being produced), to reach it I press the cone down with my bare hands to its suspension limits, but carefully and with old subs I reach that . With Hertz and Daytons I have, I do not reach that point at all, where voice coil former hits the pole piece. So sad for such a pumped with muscle sub
(No doubt dayton will reach its excur. limits earlier than the Maelstrom, but never with "nocking noise")
The whole here resembles old motor/ voice coil designs as i came across this issue with old subs long time ago. I still think the bottom limmiting factor of a sub cone excursion (as well the upper constraint) should be only the suspension, not the hit between the voice coil former and the pole piece. How do you think, guys is it a concern, ohh:doh: almost forgot this effect is captured on camera found it in youtube, here, notice what happends between second 39 and 41 (then the guy decreases the volume/power to it):