I just used the box to test all the drivers so that they were all in an enclosure that was the same for all of them. The box that im using has poly fill in it.
you said 1 cuft for a 6X8? that seems a little over sized for such a small driver.
I didnt do these test at 3 feet i did them all at 1 foot. Ive dont the test at different distances before though, the high end is usualy lower is all that really changes. Other then that the plots will still be pretty much the same overall. What i mean is the cerwin vega will still have the most high end, the alpine will still have the most bass it will just change the curves a little on them all.
Ive messed with mic placement, distance, using a wall or corner to increase bass i found for testing the general sound of a speaker 1-3 feet is the best.
The plots pretty just confirm what i thought i heard. What i heard was the stock speakers didnt sound bad and compareed to other 6x8 speakers they hold their own pretty well.