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Discussion Starter #1
Hey guys. I have a Ground Zero Engineering 10" Radioactive sub from their American days. Recently I bought a 12" Ground Zero passive radiator that I intend to pair up with the Radioactive.

My problem arises when I have no information on the Passive Radiator. These are not made by the now German owned Ground Zero and they do not have any information on them.

I know that passive radiators are finnicky in general and could really use the specs to properly design a new enclosure. I take it I would need to know the following - XMAX, Fs, Sd, Qms and Vas. Anyone have any info or advice on obtaining these numbers. Apparently they never included the passive radiator in any of their brochures but the specs have to be out there somewhere. Thanks in advance!
 

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badlieu said:
Hey guys. I have a Ground Zero Engineering 10" Radioactive sub from their American days. Recently I bought a 12" Ground Zero passive radiator that I intend to pair up with the Radioactive.

My problem arises when I have no information on the Passive Radiator. These are not made by the now German owned Ground Zero and they do not have any information on them.

I know that passive radiators are finnicky in general and could really use the specs to properly design a new enclosure. I take it I would need to know the following - XMAX, Fs, Sd, Qms and Vas. Anyone have any info or advice on obtaining these numbers. Apparently they never included the passive radiator in any of their brochures but the specs have to be out there somewhere. Thanks in advance!
i looked for info on those about a year ago....

found absolutely nothing...so i didn't buy it :)
 

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My wife's current comp set is a GZ Hydrogen set. Got it for dirt cheap from the US distributor, they (Treo Engineering was the distributor) liquidated all the GZ gear when GZ stopped selling in the US due to lack of sales. Its a nice little speaker set.
 

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Discussion Starter #4
Thanks guys - I knew it would be a long shot finding these specs.

I have an Orion H2 for daily use and am just messing around with the Ground Zero stuff (the Radioactive was my first sub - got it when it came out). The Radioactive was in a .77 cube sealed box that sounded pretty decent but apparently isn't ideal for the sub. The box is wedge shaped and I ended up cutting the back out today and dropping in the passive radiator. Definitely a huge improvement, plays lower and cleaner. I took it out of my car today and stuffed it with a good amount of polyfill and auditioned it in the garage and not in car - definitely sounds even better now.

I may decide to run the sub and passive radiator into a sonotube sub for home use and would probably opt for a bit more airspace if so.

For those who didn't know - a slightly altered version of the Ground Zero Nuke's were used in the first version of Bob Carvers Sunfire Subs. Pretty cool!
 

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Discussion Starter #5
I'm still looking for specs on the Ground Zero 12" Passive Radiator (1990's).

I want to mess around with WinISD but I need the Vas, Qms, Fs, Sd and XMAX to do so. I want to build a new box but would love to avoid guessing. Anyway to find/figure out any of the specs?

Here's specs for the 10" Ground Zero driver I will be using with the PR -

Fs: 40 Hz
Re: 3.3 Ohms
Qt: .383
Qe: .396
Qm: 11.4
Vas: 30.9 Liters
SD: .0322 M^2
BL: 12.5
Le: 1.9 mH
Power handling 250 watts
 

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It's not intuitive and I still don't believe it :D, but for a passive radiator system the only parameter that seems to matter is the weight of the cone. You'll still need to find that but you can determine it experimentally by building a large box, installing the woofer and PR, and backing the weight out by determining the tuning frequency.

see http://www.diysubwoofers.org/prd/ for description on how to design a passive radiator system (and the eq's you'll need to find the mass of the PR).
 
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