[Blaine_M]

We have my friends box done, used the plans on the site.  How much wieght do we add to the PR?  I'm assuming washers are used, what size of washers and what size of nut do you use on that thing?  Also how much poly fill should we use?  The box is lined with Black Hole 5 if that makes a difference.

[wmeckle]

We have my friends box done, used the plans on the site.  How much wieght do we add to the PR?  I'm assuming washers are used, what size of washers and what size of nut do you use on that thing?  Also how much poly fill should we use?  The box is lined with Black Hole 5 if that makes a difference.

The following advice is from Ken Kantor (former CEO and co-founder of NHT)
"Exact enclosure volume is not critical, and stuffing can be added or subtracted to fine tune the response.  I  recommend adjusting the stuffing by monitoring the impedance versus frequency
of the sealed box system.  Add stuffing to lower the frequency where the impedance is highest.  When that impedance peak starts to rise in frequency, you have added too much."
Hope this helps.

[Blaine_M]

Well, that sort of helps.  How does the average Joe measure that stuff?  Also not sure how much wieght to put on the radiator still and what size of nut that uses.

[wmeckle]

Well, that sort of helps.  How does the average Joe measure that stuff?  Also not sure how much wieght to put on the radiator still and what size of nut that uses.

Sorry, the instructions only apply to a sealed box.

[Danny Richie]

Blaine,

The PR is already at optimal weight to tune the SW-12A in a 2.4 cubic foot box to a tuning frequency of 22Hz and it will give you a -3db down point of 20Hz. Unless you are changing the box size, you will not have to change the tuning.

Blackhole 5 will be fine alone, but you can add poly fill or fiberglass insulation to further lower (slightly) or fine tune the tuning.