Because that was the OP's question when they posted.
Personally, as a consumer of goods and services, I don't see a valid reason why sealed, ported, duals or radiated subs can't be directly compared. In the end they're going be used for a single purpose, sound reproduction and the consumer of the purchased goods or services is the final arbiter, not a reviewer, you, me or some over intellectualizing lamp post.
If one manufacture wants to make and sell a dual driver subwoofer and another manufacture wants to build and sell single driver subwoofers to consumers, I'm all for them doing so and if a consumer wants to compare a pair of single driver subs to a quad setup of dual driver subs, or purchase and integrate one of each into their listening room's acoustics, I'm all for them doing so. It's their money, their questions; their mental health funeral.
When it comes to consumerism, there are no rules, there's only getting the best bang for available bucks. Consumers get to freely choose their AVR, accompanying appliances, TV, speakers, subwoofers and room to put it all in and bless those willing to put forth the effort to try and make it all happen.
Maybe Marantz should be allowed to only sell AVR's with XT32 installed. Maybe subwoofer manufactures should only be allowed to manufacture to the highest consumer standards. Maybe it should be, only upon completion of accredited appropriate room analyzing course work at local level community colleges, a degree/license needs to be issued before one is personally allowed to buy and install ID purchased subwoofers. And like an online pharmacy, if the individual doesn't have the required license in hand, they can only buy from outlets like BB and they must purchase "Geek Squad" installation services before turning their AVR on.
Edited by BeeMan458 - 2/6/13 at 4:13am