they are loud but must be ported.put 2 cuft on each w/a 4inch round port 7.5 inches long,they will hit hard.tuning will be at about 39-40hz.good all around and LOUD.I had them in a coupe civic,in the trunck firing towards the back of the trunk. It hit 138dbs with 225wts on each sub with celine dion,"my heart will go on"on the titanic soundtrack.that was the only time i had it metered.