Now I'm not here to argue about how much better higher wattage ones could be, since I already own these, it seems counter productive to tell me to throw these out when I could have fun making a case for it. For $60/ea $120/pair these are keeping up with the orginal drivers in my yorkville SW1000 subwoofers, that would've cost me $450/ea $900/total to replace from long n mcquade.
What I'd like to do is put them to use and use a case that could give them a bit more bump (since they prob need it being cheap drivers) and since I already own two of them and got a bunch of mdf I can easily build and test a prototype cab without spending any money.
I've thought about making a gsub/dual reflex with them or a value buster subwoofer system (vbss for short that uses a cheap $90 18 inch dayton driver) or a 4th order cab (like car audio 4th order walls) or a cubo 18, but I wonder how effective these cases are for these drivers since most of these cases (aside of the vbss) have been designed with higher wattage drivers with more xmax in mind.
When I put them into winISD, when it asks you what type of box your building it says the driver has a EBP of 54.2 making it better for a closed or 4th order box if I'm looking at this correctly. (The graphic is going up to just under half way) So this got me looking into into 4th order designs but that seems to be more of a car audio thing while I'm looking to use these as outdoor PA at ranges of 1 to 30 or 40 feet, it makes me wonder how effective a 4th order or vbss would be at that range verse something like a cubo or dual reflex that are obviously meant for longer ranges.
For around $250 - $350 you can find very good 18" drivers, so it seems silly to spend $450 for the original driver.
A 4th order BP is not often used in PA systems for the low end, nor is a closed cabinet. WinISD comes up with this suggestion due to the high Qes/Qts of this driver (it has a weak motor). Considering the use for PA a reflex is still the best option, though due to the high Qts it does become a compromise. The high Qts combined with high Vas asks for a large reflex enclosure but budget drivers do not have the power handling to make use of this enclosure beyond medium SPL levels. So these drivers are typically put in enclosures that are smaller then optimum to boost the power handling somewhat.
The Dayton 460-8 Pro is similar to your driver but it has a much lower Qts, which makes it suitable for a wider range of and/ or smaller enclosures.The gsub is aimed at Qts < 0.4, the vbss looks aimed for use at home, which is where I think the Rockfords would shine brightest.
If you want most output Cubo 18 Standard is an option for PA, especially since all options are going to be compromises at this point.