[Kevin Haskins]

I've got stock of the new Passive Radiators, both 15" & 18" versions to go with our current lineup of drivers.

I'm working on documentation.   Here are a few pictures of the EX-PR15.   The basket and cone are the same as used on the Tempest.   The surround is slightly different and it has a larger dust cap.  Otherwise it looks pretty much the same when mounted and uses the same mounting dimensions.




We use a standard spider with a small former with an MDF disc & t-nut glued into the base.   The T-nut is for the mass kit, which includes a bolt, washers, and a gaggle of 100g disc for adjusting the mass.   

Here is a picture without the mass kit installed. 



And a picture with the mass in place.   This arrangement allows the designer to add up to almost 1800g to the PR15 and about 2000g on the PR18.   You can adjust the tuning in about 100g increments.   




I'll have more pictures of the PR18 tomorrow. 

Parameters:

Fp:  Resonance frequency (in free-air with no added mass)   20.0 Hz
Qmp:  Mechanical compliance loss                                      6.0
Mmp:  Moving mass                                                         200g
Cms:  Suspension Compliance                                             0.28 mm/N
Vap: Stiffness of driver scaled by cone size                           245L
Sd:  Area of the cone                                                        791 cm^2
Suspension Travel                                                         32-35mm  Somewhere around 60-70mm peak-peak, depending on how far you stretch the suspension.   The system will not bottom mechanically until 40mm (one way) but you are likely to damage the suspension before that limit. 

[Kevin Haskins]

Here is the PDF documentation.   If you guys could give it a quick once over for bo-boos I'd appreciate the feedback.

http://www.diycable.com/main/pdf/PR15.pdf

[dyohn]

The PDF looks clean Kevin.  I didn't notice any gross grammatical or punctuation mistakes.  You may want to update your copyright notice to 2008, but other than that...

Man, bolt a motor onto that structure and you'd have ... what, a Tempest?  An original Maelstrom?

[Kevin Haskins]

The PDF looks clean Kevin.  I didn't notice any gross grammatical or punctuation mistakes.  You may want to update your copyright notice to 2008, but other than that...

Man, bolt a motor onto that structure and you'd have ... what, a Tempest?  An original Maelstrom?

It is a current Tempest basket & cone with a slightly different spider & surround.   I don't remember what Dan used on the original Maelstrom???   I guess I'm getting old but I think it was a stamped steel basket.   The new Maelstrom is really not at all related to the old one.   It has more similarity to the old Tumult motor, with updated inductance rings. 

They are all continuously in flux.   I'm making some changes to the next generation right now.   The new Tempest is getting updated to the CuAl shorting rings (it currently only has an aluminum one in the rebate), an updated spider with tinsel leads integrated into the spider and a little more progressive profile.  The voice coil is going to get a little longer to give us a peak in the BL curve at center, a little less stroke and it is going to be a single 4 Ohm coil rather than dual 8s.   

Anyway... thanks for catching the Copyright date.  I'll update it.

Here are the PR-18 pictures.    Same concept except super-size it to match up with the Maelstrom-X.   It uses the Maelstrom-X basket so all mounting dimensions are the same.   (18.5" OD, 17" cut-out, 7" depth)












And here are the components of the Mass Kit.   

[dyohn]

That is a truly beautiful PR.  Like most of your designs, it's too bad all that mechanical beauty gets hidden inside the enclosure.  Yea, as I recall the original DW Maelstrom used a stamped basket.  The Tumult was a fantastic driver - one of my all-time favorites - so if the new Maelstrom is related to it, it should be a killer especially at your super low price.